Patent Publication Number: US-2021178453-A1

Title: Coil winding apparatus and coil winding method

Description:
TECHNICAL FIELD 
     The present invention relates to a coil winding apparatus and a coil winding method. 
     BACKGROUND ART 
     Generally, there is a known heater element for an electronic cigarette that is formed by processing a wire rod made of a high resistivity alloy (for example, Nichrome, aldirom, constantan alloy, and so forth) into a predetermined shape (JP2016-507137A). With this heater element, a smoking effect is generated by atomizing a smoking liquid when energized. In order to atomize the smoking liquid efficiently, such a wire rod may be wound in a spiral manner around a core rod to be impregnated with the smoking liquid. According to such a heater element, the smoking liquid impregnated into the core rod may be efficiently atomized by the wire rod that is energized and heated. 
     SUMMARY OF INVENTION 
     Because the wire rod used to form the heater element made of the high resistivity alloy needs to be processed to a predetermined shape, the wire rod has a flexibility, but also, it is relatively rigid. Because the smoking liquid needs to be impregnated, the core rod is often formed into a string shape by binding heat resistive fibers such as glass fibers. The core rod having the string shape formed by binding such fibers is relatively soft. Therefore, in the manufacture of the heater element, the relatively rigid wire rod is wound around the relatively soft string-shaped core rod in a spiral manner. Thus, mechanization of manufacturing steps of the heater element is difficult, and in reality, many steps are performed by manual operations. 
     An object of the present invention is to provide a coil winding apparatus and a coil winding method that are capable of winding a relatively rigid wire rod around a relatively soft string-shaped core rod in a spiral manner. 
     According to an embodiment of the present invention, a coil winding apparatus includes: a core rod feeding unit configured to feed a string-shaped core rod from a core rod nozzle at a constant tension; a core rod drawing unit configured to draw out the core rod from the core rod nozzle against the tension by holding the core rod that has been fed from the core rod nozzle; a wire rod feeding unit configured to feed a wire rod towards the core rod that has been drawn out from the core rod nozzle, the wire rod being fed in a direction intersecting with a drawing direction of the core rod; a rotator into which the core rod nozzle is inserted, the rotator being capable of rotating about the core rod nozzle; a guide member provided on an end portion of the rotator with shift respect to a center of the rotator, the guide member being configured to clamp, with the core rod, the wire rod that has been fed from the wire rod feeding unit; and a rotating unit configured to rotate the rotator to rotate the guide member together with the rotator so as to revolve the wire rod around the core rod in a vicinity of the core rod nozzle. 
     According to another embodiment of the present invention, the coil winding is a winding method for winding the wire rod around the string-shaped core rod in a spiral manner, and in the coil winding method, the core rod is inserted through the core rod nozzle while applying a predetermined tension to the core rod, and the wire rod is revolved around the core rod in the vicinity of the core rod nozzle while drawing out the core rod from the core rod nozzle against the tension. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a plan view showing a coil winding apparatus of an embodiment according to the present invention. 
         FIG. 2  is a front view of the coil winding apparatus shown in  FIG. 1 . 
         FIG. 3  is a sectional view taken along a line III-III in  FIG. 1  and shows a state in which a wire rod has been fed towards a core rod from the direction intersecting the core rod. 
         FIG. 4  is a perspective view showing a state in which the wire rod is wound around the core rod in a spiral manner by the coil winding apparatus. 
         FIG. 5  is a diagram corresponding to  FIG. 3  and shows a state in which the wire rod is projected from a wire rod nozzle by moving the wire rod nozzle that has fed the wire rod away from the core rod. 
         FIG. 6  is a diagram corresponding to  FIG. 5  and shows a state in which the wire rod is intersecting with the core rod by moving, together with the wire rod, the wire rod nozzle from which the wire rod is projecting. 
         FIG. 7  is a diagram corresponding to  FIG. 6  and shows a state in which the wire rod is suspended on the core rod by being turned. 
         FIG. 8  is a diagram corresponding to  FIG. 7  and shows a state in which the wire rod nozzle is moved away from the core rod again, and another portion of the wire rod is fed. 
         FIG. 9  is a diagram corresponding to  FIG. 8  and shows a state in which the wire rod after it has been wound is cut. 
         FIG. 10  is a perspective view of a coil formed by winding the wire rod around the core rod in a spiral manner. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Next, a coil winding apparatus and a coil winding method according to an embodiment of the present invention will be described with reference to the drawings. 
       FIG. 10  shows a coil  8  obtained by the present embodiment. The coil  8  forms, for example, a heater element of an electronic cigarette. Specifically, the coil  8  is formed by winding a wire rod  12  around a core rod  11  in a spiral manner. The core rod  11  in the present embodiment is a member that is formed into a string shape by binding a bundle of heat resistive fibers such as glass fibers. The wire rod  12  is, for example, a Nichrome wire made of a high resistivity alloy, and its rigidity is higher than the core rod  11 . 
     In the heater element of the electronic cigarette, if there is a gap between the wire rod  12  and the core rod  11  or if the core rod  11  is squeezed too much, a liquid is not supplied around the wire rod  12  sufficiently. As a result, there is a possibility that the wire rod  12  is burned. For such a reason, it is required to wind the wire rod  12  in moderate close contact without gaps around the core rod  11 . Further, the string-shaped core rod  11  is soft and has an unstable diameter. When the diameter of the core rod  11  is varied, which has been formed by winding the wire rod  12  in moderate close contact without gaps around the core rod  11 , is also varied. As the inner diameter of the spiral member is varied, a length of the wire rod  12  is also varied, and in turn, the electrical resistance is varied. Thus, it is important to control the inner diameter of the spiral member (an electrical resistance control). In the heater element of the electronic cigarette, the electrical resistance of the wire rod  12  is a factor that determines an amount and taste of a liquid smoke, and the electrical resistance control is extremely important. 
     According to the present embodiment, the relatively rigid wire rod  12  may be wound around the relatively soft string-shaped core rod  11  in a spiral manner. Further, according to the present embodiment, the wire rod  12  may be wound around the core rod  11  at the same inner diameter in a spiral manner without forming a gap between the core rod  11  and the wire rod  12 . 
       FIGS. 1 to 3  show a coil winding apparatus  20  according to the present embodiment. In the figures, the X axis, the Y axis and, the Z axis that are orthogonal to each other are set, and the configuration of the coil winding apparatus  20  will be described. The X axis is an axis extending in the substantially horizontal longitudinal direction, the Y axis is an axis extending in the substantially horizontal transverse direction, and the Z axis is an axis extending in the substantially vertical direction. 
     The coil winding apparatus  20  is provided with core rod feeding unit  21  that feeds the string-shaped core rod  11  made of a bundle of fibers from a core rod nozzle  22  at a constant tension. As shown in  FIG. 2 , the core rod  11  is stored by being wound on a core rod spool  23 , and the core rod  11  is guided to the core rod nozzle  22  by being unwound from the core rod spool  23 . A core rod tension device  24  for applying the constant tension to the core rod  11  is provided between the core rod spool  23  and the core rod nozzle  22 . 
     The core rod tension device  24  is configured so as to be capable of applying the tension to the core rod  11  and pulling back the core rod  11 . The core rod tension device  24  is provided with a casing  26  that is provided on a mounting  19  and a tension bar  27  that is provided on a side surface of the casing  26  in the X axis direction so as to extend along the side surface. 
     The core rod spool  23  is provided on the side surface of the casing  26  in the X axis direction. A feeding control motor  28  that rotates the core rod spool  23  to feed the core rod  11  is provided in the inside of the casing  26 . A core rod guide pulley  29  is provided on a distal end of the tension bar  27 . The core rod  11  is fed from the core rod spool  23  and guided to the core rod guide pulley  29 , and thereby, the core rod  11  is wired from the core rod guide pulley  29  so as to be inserted through the core rod nozzle  22 . 
     A turning shaft  27   a  that extends in the X axis direction is provided on a proximal end of the tension bar  27 , and the tension bar  27  is configured so as to be able to turn about the turning shaft  27   a . The turning angle of the turning shaft  27   a  is detected by a potentiometer  30  serving as turning angle detection means that is accommodated in the casing  26  and mounted to the turning shaft  27   a . A detection output from the potentiometer  30  is input to a controller (not shown), and a control output from the controller is linked to the feeding control motor  28 . 
     At a predetermined position between the turning shaft  27   a  of the tension bar  27  and the core rod guide pulley  29 , a spring  31  that is an elastic member serving as biasing means is mounted at one end thereof via a mounting bracket  27   b . The spring  31  biases the tension bar  27  towards the turning direction of the tension bar  27 . The tension bar  27  receives an elastic force from the spring  31  correspondingly to the turning angle. Other end of the spring  31  is fixed to a moving member  32 . The moving member  32  is screwed to a tension adjusting screw  33  and is configured such that the movement thereof can be adjusted in accordance with rotation of the tension adjusting screw  33 . In other words, the position at which the other end of the spring  31  is fixed can be changed, and thereby, the tension of the core rod  11  that is applied by the tension bar  27  can be adjusted. 
     The controller (not shown) is configured so as to control the feeding control motor  28  such that the turning angle detected by the potentiometer  30  becomes a predetermined angle. Therefore, in the core rod tension device  24 , the tension is applied to the core rod  11  by the spring  31  via the tension bar  27 , and the core rod spool  23  is rotated such that the turning angle of the tension bar  27  becomes a predetermined angle, and thereby, the core rod  11  is fed at a predetermined amount. Thus, the tension of the core rod  11  is maintained at a predetermined level. 
     As shown in an enlarged view in  FIG. 2 , the core rod nozzle  22  in the present embodiment is a straight cylindrical member having an inner diameter smaller than an outer diameter of the core rod  11  in a natural state. The core rod nozzle  22  extends in the Y axis direction, and a proximal end of the core rod nozzle  22  is mounted to a first support pillar  36  erected on the mounting  19 . The inner diameter of the core rod nozzle  22  is set such that the core rod  11  that has been stretched and its outer diameter has been suitably reduced can pass through. 
     The coil winding apparatus  20  is provided with a rotator  37  into which the core rod nozzle  22  is inserted. The rotator  37  rotates about the core rod nozzle  22 . Specifically, a second support pillar  38  erects on the mounting  19  so as to be separated away from the first support pillar  36  in the Y axis direction, and the rotator  37  having a cylindrical shape is provided on the second support pillar  38 . The core rod nozzle  22  is inserted through the rotator  37  having the cylindrical shape. The rotator  37  is provided on the second support pillar  38  via a bearing  39  so as to be rotatable about the core rod nozzle  22 . 
     The rotator  37  projects from the second support pillar  38  towards the first support pillar  36 . A pulley  41  is fitted to a projecting end of the rotator  37 . A motor  42  serving as a rotating means that rotates the rotator  37  is provided on the second support pillar  38 . The motor  42  has a rotating shaft  42   a  that is in parallel with the rotator  37 . In addition to the pulley  41 , a pulley  43  is provided on the rotating shaft  42   a  of the motor  42 . The motor  42  may be provided on the mounting  19 . 
     A belt  44  is suspended between the pulley  41  of the rotator  37  and the pulley  43  on the rotating shaft  42   a  of the motor  42 . As the motor  42  is driven, rotation of the rotating shaft  42   a  is transmitted to the rotator  37  via the belt  44 , and the rotator  37  is rotated. 
     As shown in  FIGS. 1 and 2 , the coil winding apparatus  20  is provided with a core rod drawing unit  50  that holds the core rod  11 , which has been inserted through the core rod nozzle  22 , and that draws out the core rod  11  from the core rod nozzle  22 . The core rod drawing unit  50  in the present embodiment is provided with a core rod holding device  51  that is configured such that a pair of clamping blocks  51   a  and  51   b  are opened and closed by a fluid pressure and the core rod  11  can be held by the clamping blocks  51   a  and  51   b , a motor  49  that rotates the core rod holding device  51  about the core rod  11  that has been held, and a core-rod-holding-device moving mechanism  52  that is capable of moving the core rod holding device  51 , together with the motor  49 , in three axial directions. 
     The core-rod-holding-device moving mechanism  52  illustrated in  FIGS. 1 and 2  is configured by combining X axis, Y axis, and Z axis direction telescopic actuators  56  to  58 . In other words, the telescopic actuators  56  to  58  have, respectively, elongated box-shaped housings  56   d  to  58   d , ball screws  56   b  to  58   b  that are provided so as to extend in the housings  56   d  to  58   d  in the lengthwise directions and that are respectively rotationally driven by servo motors  56   a  to  58   a , and followers  56   c  to  58   c  that are respectively screwed to the ball screws  56   b  to  58   b  and undergo translation movement. 
     In the present embodiment, the core rod holding device  51  is mounted to a rotating shaft  49   a  of the motor  49 , the motor  49  is mounted to the housing  57   d  of the Y axis direction telescopic actuator  57  so as to be able to move the core rod holding device  51  in the Y axis direction, and the follower  57   c  of the Y axis direction telescopic actuator  57  is mounted to the follower  58   c  of the Z axis direction telescopic actuator  58  so as to be able to move, together with the Y axis direction telescopic actuator  57 , the core rod holding device  51  in the Z axis direction. Further, the housing  58   d  of the Z axis direction telescopic actuator  58  is mounted to the follower  56   c  of the X axis direction telescopic actuator  56  so as to be able to move, together with the Y axis and Z axis direction telescopic actuators  57  and  58 , the core rod holding device  51  in the X axis direction. The housing  56   d  of the X axis direction telescopic actuator  56  is fixed to the mounting  19  so as to extend in the X axis direction. 
     The servo motors  56   a  to  58   a  in the telescopic actuators  56  to  58  are connected to a controller (not shown), and they are controlled by the controller. In other words, with the telescopic actuators  56  to  58 , as the servo motors  56   a  to  58   a  are driven by commands from the controller (not shown), the ball screws  56   b  to  58   b  are rotated, and thereby, the followers  56   c  to  58   c  screwed to the ball screws  56   b  to  58   b  are moved along the lengthwise direction of the housings  56   d  to  58   d . As the followers  56   c  to  58   c  are moved, the core rod holding device  51  is moved in three axial directions. 
     The core rod holding device  51  with the pair of opening clamping blocks  51   a  and  51   b  is moved such that the core rod  11  projecting from a distal end of the core rod nozzle  22  is positioned between the pair of clamping blocks  51   a  and  51   b , and thereafter, the pair of clamping blocks  51   a  and  51   b  are closed to hold the core rod  11  with the pair of clamping blocks  51   a  and  51   b . In addition, by moving the core rod holding device  51  in the direction away from the core rod nozzle  22  while holding the core rod  11 , the core rod  11  is drawn out from the core rod nozzle  22 . As described above, the core rod drawing unit  50  is configured so as to hold the core rod  11  inserted into the core rod nozzle  22  and draw the core rod  11  out from the core rod nozzle  22 . 
     A core rod clamping tool  53  is provided on the mounting  19 . In the core rod clamping tool  53 , the core rod  11  extending from the core rod tension device  24  to the core rod nozzle  22  is clamped by clamping blocks  53   a  at the vicinity of the first support pillar  36 , thereby prohibiting the movement of the core rod  11  towards the core rod nozzle  22 . 
     The core rod clamping tool  53  shown in  FIG. 2  is a so-called fluid pressure cylinder. Specifically, in the core rod clamping tool  53 , the pair of clamping blocks  53   a  are moved so as to be separated away from each other or so as to come closer with each other by using fluid pressure. By moving the pair of clamping blocks  53   a  so as to come closer with each other in a state in which the core rod  11  is passed through between the separated pair of clamping blocks  53   a , the core rod  11  is claimed. In the core rod clamping tool  53 , a main body  54   b  is mounted to an upper end of a retracting shaft  54   a  of a fluid pressure cylinder  54  that is provided on the mounting  19  such that the retracting shaft  54   a  is orientated vertically. The fluid pressure cylinder  54  lowers the core rod clamping tool  53  that is not clamping the core rod  11 . Thereby, the core rod clamping tool  53  is moved to a position where routing of the core rod  11  is not interfered. 
     As shown in  FIGS. 1 and 3 , the coil winding apparatus  20  is provided with a wire rod feeding unit  60  that feeds the wire rod  12  to the core rod  11  that has been inserted through and drawn out from the core rod nozzle  22 . The wire rod  12  is fed in the direction orthogonal to the core rod nozzle  22 . The wire rod feeding unit  60  is provided with a wire rod nozzle  61  through which the wire rod  12  is inserted and a wire-rod-nozzle moving mechanism  62  that moves the wire rod nozzle  61  in the three axial directions. 
     The wire-rod-nozzle moving mechanism  62  is configured so as to be capable of moving a support plate  66  in the three axial directions with respect to the mounting  19 . The wire-rod-nozzle moving mechanism  62  has the same structure with that of the above-described core-rod-holding-device moving mechanism  52 . Specifically, the wire-rod-nozzle moving mechanism  62  is provided with an X axis direction telescopic actuator  63  that moves the support plate  66  in the X axis direction, a Z axis direction telescopic actuator  65  that moves, together with the X axis direction telescopic actuator  63 , the support plate  66  in the Z axis direction, and a Y axis direction telescopic actuator  64  that moves, together with the X axis and the Z axis direction telescopic actuator  63  and  65 , the support plate  66  in the Y axis direction. 
     The support plate  66  is mounted to a housing  63   d  of the X axis direction telescopic actuator  63 . A follower  63   c  of the X axis direction telescopic actuator  63  is mounted to a follower  65   c  of the Z axis direction telescopic actuator  65 . A housing  65   d  of the Z axis direction telescopic actuator  65  is mounted to a follower  64   c  of the Y axis direction telescopic actuator  64 . A housing  64   d  of the Y axis direction telescopic actuator  64  is fixed to the mounting  19  so as to extend in the Y axis direction. Servo motors  63   a  to  65   a  in the telescopic actuators  63  to  65  are connected to a controller (not shown) that controls these components. The servo motors  63   a  to  65   a  respectively rotate ball screws  63   b  to  65   b  of the telescopic actuators  63  to  65 . 
     The support plate  66  supports a fluid pressure cylinder  68 . A main body portion  68   b  of the fluid pressure cylinder  68  is mounted to the support plate  66  such that an retracting rod  68   a  of the fluid pressure cylinder  68  extends in the X axis direction. A mounting plate  67  is mounted on a projecting end of the retracting rod  68   a . The wire rod nozzle  61  is mounted on the mounting plate  67  so as to face towards the X axis direction. 
     In addition, the support plate  66  supports a proximal end nozzle  69  that is provided coaxially with the wire rod nozzle  61  and a wire rod clamping tool  71  that is provided in the vicinity of the proximal end nozzle  69 . In the wire rod clamping tool  71 , a pair of clamping blocks  71   a  clamp the wire rod  12  that has passed through the proximal end nozzle  69  towards the wire rod nozzle  61  so as to be releasable. Because a fluid pressure cylinder having the same structure as that of the core rod clamping tool  53  that clamps the core rod  11  is used for the wire rod clamping tool  71 , detailed descriptions of the wire rod clamping tool  71  will be omitted. 
     As shown in  FIG. 3 , in addition to the fluid pressure cylinder  68  and the wire rod clamping tool  71 , the support plate  66  supports a cutter device  59 . The cutter device  59  uses air pressure to cut the wire rod  12  that has passed through the wire rod nozzle  61  and the core rod  11  that has passed through the core rod nozzle  22 . The cutter device  59  is mounted on a rotating cylinder  73 , the rotating cylinder  73  is mounted on an elevating cylinder  72 , and the elevating cylinder  72  is mounted on the support plate  66 . The elevating cylinder  72  is driven by a command from a controller (not shown) to move the rotating cylinder  73  and the cutter device  59  up and down. The rotating cylinder  73  rotates the cutter device  59  about the vertical axis. 
     The cutter device  59  is lowered by the elevating cylinder  72 , and thereby, cutter blades  59   b  are moved to cutting positions for cutting the wire rod  12  and the core rod  11 . In addition, the cutter device  59  is lifted by the elevating cylinder  72 , and thereby, the cutter blades  59   b  are moved to a stand-by position away from the wire rod  12  and the core rod  11 . The cutter device  59  is rotated by the rotating cylinder  73  about the vertical axis, and thereby, the cutter device  59  is switched from a wire rod cutting orientation in which the cutter blades  59   b  pinch and cut the wire rod  12  to a core rod cutting orientation in which the cutter blades  59   b  pinch and cut the core rod  11  extending orthogonal to the wire rod  12 . 
     As shown in  FIGS. 1 and 3 , similarly to the core rod  11 , the wire rod  12  is stored by being wound on a wire rod spool  74 . The wire rod  12  that is unwound and fed from the wire rod spool  74  is inserted through the proximal end nozzle  69  and the wire rod nozzle  61  in this order. The coil winding apparatus  20  is provided with a wire rod tension device  75  that applies a predetermined tension to the wire rod  12  that has been unwound from the wire rod spool  74 . 
     The wire rod tension device  75  in the present embodiment has substantially the same structure as the structure of the core rod tension device  24  (see  FIG. 2 ) that applies a predetermined tension to the core rod  11 . In other words, the wire rod tension device  75  is provided with a casing  76  that is provided on the mounting  19  and a tension bar  77  that is provided on a side surface of the casing  76  in the Y axis direction so as to extend along the side surface. The wire rod spool  74  is provided on the side surface of the casing  76 . A feeding control motor  78  that rotates the wire rod spool  74  is provided in an interior of the casing  76 . A wire rod guide pulley  79  is provided on a distal end of the tension bar  77 . A rotating shaft  77   a  is provided on a proximal end of the tension bar  77 , and a potentiometer  80  that detects the turning angle of the rotating shaft  77   a  is provided in the casing  76 . 
     As shown in  FIG. 3 , one end of a spring  81  is mounted on the tension bar  77  via a mounting bracket  77   b . Other end of the spring  81  is fixed to a moving member  82 . The moving member  82  is screwed to a tension adjusting screw  83  and is configured such that the movement thereof can be adjusted in accordance with rotation of the tension adjusting screw  83 . 
     In other words, in the wire rod tension device  75 , the tension is applied to the wire rod  12  by the spring  81  via the tension bar  77 . In addition, the wire rod spool  74  is rotated by controlling the feeding control motor  78  such that the tension bar  77  is oriented in a predetermined angle, in other words, such that the turning angle detected by the potentiometer  80  becomes a predetermined angle, and the wire rod  12  is fed at a predetermined amount. Thereby, the tension of the wire rod  12  is maintained at a predetermined level. 
     As shown in  FIGS. 1 to 3 , the core rod  11  is fed from a feeding-side end portion of the rotator  37  into which the core rod nozzle  22  is inserted. A guide member  86  is provided on the feeding-side end portion of the rotator  37  with shift respect to the rotation center of the feeding-side end portion. The guide member  86  clamps the wire rod  12  that has been fed from the wire rod feeding unit  60  with the core rod  11  that has been drawn out from the core rod nozzle  22 . As the motor  42  serving as the rotating means rotates the rotator  37 , as shown in  FIG. 4 , the guide member  86  is rotated together with the rotator  37 , and thereby, the wire rod  12  that is clamped with the core rod  11  is guided around and rubbed and placed onto the core rod  11  in the vicinity of the core rod nozzle  22 . Thus, the wire rod  12  revolves around the core rod  11 . The phrase “in the vicinity of the core rod nozzle  22 ” means, for example, a region from a feeding-side end portion of the core rod nozzle  22  to the center of a gap between the core rod nozzle  22  and the pair of clamping blocks  51   a  and  51   b.    
     As shown in  FIG. 4 , the guide member  86  in the present embodiment is a pulley that is pivotably supported on an end portion of the rotator  37 . The pulley can easily guide the wire rod  12  around the core rod  11  in the vicinity of the core rod nozzle  22  by being rotated in a state in which the wire rod  12  is suspended. 
     As shown in  FIGS. 1 to 3 , a receiving tool  93  is provided under the feeding-side end portion of the core rod nozzle  22 . The receiving tool  93  receives the coil  8  that is formed by winding the wire rod  12  around the core rod  11  in a spiral manner. The receiving tool  93  is mounted on a fluid pressure cylinder  92 , and the fluid pressure cylinder  92  is mounted on a follower  91   c  of a telescopic actuator  91 . A housing  91   d  of the telescopic actuator  91  is mounted on the mounting  19  so as to extend in the X axis direction. 
     A main body  92   b  of the fluid pressure cylinder  92  is mounted on the follower  91   c  of the telescopic actuator  91  such that an retracting shaft  92   a  of the fluid pressure cylinder  92  faces upwards. The receiving tool  93  is mounted on an upper end of the retracting shaft  92   a  of the fluid pressure cylinder  92 . A recessed groove  93   a  capable of receiving the coil  8  (see  FIG. 10 ) is formed on a top portion of the receiving tool  93  so as to be in parallel with the feeding direction of the core rod  11 . In a state in which the coil  8  is received in the recessed groove  93   a , the receiving tool  93  is lowered by the fluid pressure cylinder  92  and is further moved in the X axis direction by the telescopic actuator  91 , and thereby, the coil  8  thus obtained can be taken out to the outside. 
     Next, a coil winding method of the present invention will be described. 
     In the coil winding method of the present invention, the wire rod  12  is wound around the string-shaped core rod  11  in a spiral manner. The coil winding method is characterized in that the core rod  11  is inserted through the core rod nozzle  22  while applying a predetermined tension to the core rod  11 , and the wire rod  12  is revolved around the core rod  11  in the vicinity of the core rod nozzle  22  while drawing out the core rod  11  from the core rod nozzle  22  against a tensile force. 
     The coil winding method is performed on the above-described coil winding apparatus  20 . In other words, as shown in  FIG. 4 , in the coil winding apparatus  20 , the wire rod  12  is fed from the direction orthogonal to the core rod  11  that has been drawn out from the core rod nozzle  22 , the wire rod  12  is clamped by the core rod  11  and the guide member  86  in the vicinity of the core rod nozzle  22 , and the guide member  86  is rotated about the core rod  11 . By doing so, a distal-end side wire rod  12   a  extending beyond the guide member  86  is continuously suspended on the guide member  86  and is revolved around the core rod  11 . 
     A procedure of the coil winding method will be described specifically. The core rod  11  and the wire rod  12  are first installed to the coil winding apparatus  20 . As shown in  FIG. 2 , the core rod  11 , which is wound and stored on the core rod spool  23 , is prepared, and the core rod spool  23  is mounted on the side surface of the casing  26  in the core rod tension device  24  such that the feeding control motor  28  can rotate the core rod spool  23 . The core rod  11  that has been unwound from the core rod spool  23  is guided to the core rod guide pulley  29  of the distal end of the tension bar  27  and inserted through the core rod nozzle  22 . 
     The core rod nozzle  22  in the present embodiment is a straight cylindrical member that has the inner diameter smaller than the outer diameter of the core rod  11  in the natural state. The core rod  11  is inserted through the core rod nozzle  22  in a state in which the core rod  11  is stretched such that the outer diameter thereof is reduced suitably. In this state, the core rod clamping tool  53  mounted on the mounting  19  is used to clamp the core rod  11 , thereby prohibiting the movement of the core rod  11 . Thus, even if the core rod  11  is pulled by the core rod tension device  24 , the core rod  11  is prevented from been pulled back from the core rod nozzle  22 . 
     As shown in  FIG. 3 , the wire rod  12  that has been wound and stored on the wire rod spool  74  is prepared, and the wire rod spool  74  is mounted on the side surface of the casing  76  of the wire rod tension device  75  such that the feeding control motor  78  can rotate the wire rod spool  74 . The wire rod  12  that has been unwound from the wire rod spool  74  is guided to the wire rod guide pulley  79  on the distal end of the tension bar  77  and is inserted through the proximal end nozzle  69  and the wire rod nozzle  61  in this order. 
     The wire rod nozzle  61  is mounted on the support plate  66  via the fluid pressure cylinder  68 . The wire rod  12  is inserted through the wire rod nozzle  61  in a state in which the retracting rod  68   a  of the fluid pressure cylinder  68  is projected from the main body portion  68   b . A projecting amount of the wire rod  12  from the wire rod nozzle  61  is set to a length required for allowing the core rod  11  and the wire rod  12  to intersect with each other. In this state, the wire rod clamping tool  71  provided on the support plate  66  is used to clamp the wire rod  12 , thereby prohibiting the movement of the wire rod  12 . Thus, even if the wire rod  12  is pulled by the wire rod tension device  75  towards the wire rod tension device  75 , the wire rod  12  is prevented from been pulled back from the wire rod nozzle  61 . 
     In addition, the motor  42  serving as the rotating means is driven to rotate the rotator  37 , and thereby, the guide member  86  provided on a tip end of the rotator  37  is positioned on an imaginary place that is in parallel with the core rod  11  and orthogonal to the feeding direction of the wire rod  12  (above the core rod  11  in  FIG. 3 ). The wire rod  12  is then moved so as to intersect with the core rod  11  from the direction intersecting with the core rod  11  that has been inserted through and drawn out from the core rod nozzle  22 . The movement of the wire rod  12  is achieved by the wire-rod-nozzle moving mechanism  62 . Specifically, the wire rod nozzle  61  is moved together with the wire rod clamping tool  71 , and as shown in  FIG. 3 , the wire rod  12  that is projecting from the wire rod nozzle  61  is made to intersect with the core rod  11  in the vicinity of the core rod nozzle  22  by causing the wire rod  12  to enter a gap between the guide member  86  and the core rod  11  that is inserted through the core rod nozzle  22 . 
     Next, as shown in  FIG. 2 , the core rod  11  that has been fed from the core rod nozzle  22  is held by the core rod drawing unit  50 . Specifically, in a state in which the pair of clamping blocks  51   a  and  51   b  are separated, the core rod holding device  51  is moved by the core-rod-holding-device moving mechanism  52  to a position opposing to the distal end of the core rod nozzle  22 , and thereby, the core rod  11  is positioned between the pair of clamping blocks  51   a  and  51   b . Thereafter, the pair of clamping blocks  51   a  and  51   b  are closed, and the core rod  11  projecting from the distal end edge of the core rod nozzle  22  is clamped by the pair of clamping blocks  51   a  and  51   b.    
     By releasing the core rod  11  from the state held by the core rod clamping tool  53  provided on the mounting  19 , the feeding of the core rod  11  is allowed. By holding the core rod  11  that has been fed from the core rod nozzle  22  by the core rod drawing unit  50 , even if the core rod  11  is pulled by the core rod tension device  24 , the core rod  11  is prevented from been pulled back from the core rod nozzle  22 . 
     Next, as shown in  FIG. 5 , the retracting rod  68   a  on which the wire rod nozzle  61  of the fluid pressure cylinder  68  is mounted is moved into the main body portion  68   b , and thereby, the wire rod nozzle  61  is moved closer to the wire rod clamping tool  71  clamping the wire rod  12 . Thereby, the wire rod  12  having the length required for a subsequent winding is drawn out to a gap between the core rod  11  in the vicinity of the core rod nozzle  22  and the wire rod nozzle  61 . 
     Next, as shown in  FIG. 6 , the wire rod clamping tool  71  and the wire rod nozzle  61  are, together with the wire rod  12 , brought closer to the core rod  11  by the wire-rod-nozzle moving mechanism  62 , and thereby, the wire rod  12  that has been fed from the core rod nozzle  22  by the length required for winding is inserted between the guide member  86  and the core rod  11  so as to intersect with the core rod  11 . 
     Next, as shown in  FIG. 7 , the motor  42  serving as the rotating means is driven to rotate the rotator  37  by 180 degrees. The guide member  86  being rotated and moved comes into contact with the distal-end side wire rod  12   a  inserted between the guide member  86  and the core rod  11 , and thereby, the distal-end side wire rod  12   a  is suspended around the core rod  11  in a U shape. In this state, even if the wire rod  12  is pulled by the wire rod tension device  75  towards the wire rod tension device  75 , the wire rod  12  is prevented from been pulled back. In this state, by releasing the wire rod  12  from the state clamped by the wire rod clamping tool  71  provided on the support plate  66 , the feeding of the wire rod  12  is allowed. 
     Next, as shown in  FIG. 8 , by using the wire-rod-nozzle moving mechanism  62 , the wire rod nozzle  61  is moved, together with the wire rod clamping tool  71 , away from the core rod  11 , and the wire rod  12  is further drawn out from the wire rod nozzle  61 . After drawing out another portion of the wire rod  12  having the length required for a leader of the coil  8 , the wire rod  12  is clamped again by the wire rod clamping tool  71 . 
     Next, as shown in  FIG. 4 , while the core rod  11  is drawn out from the core rod nozzle  22 , the guide member  86  is revolved around the core rod  11  for a required number of times. Drawing of the core rod  11  is performed by the core rod drawing unit  50  shown in  FIG. 2 . Specifically, the core rod holding device  51  holding the core rod  11  is moved away from the core rod nozzle  22 , and thereby, as shown by a one-dot chain line arrow in  FIG. 4 , the core rod  11  is drawn out from the core rod nozzle  22 . 
     While the core rod  11  is being drawn out, the guide member  86  is revolved around the core rod  11 . The revolution of the guide member  86  is performed by rotating the rotator  37  by the motor  42  serving as the rotating means ( FIG. 2 ) as shown by a solid line arrow in  FIG. 4 . 
     As the guide member  86  is revolved in the vicinity of the core rod nozzle  22 , the distal-end side wire rod  12   a  passed through between the guide member  86  and the core rod  11  is continuously suspended on the guide member  86 . As the guide member  86  on which the distal-end side wire rod  12   a  is suspended is further revolved around the core rod  11 , the distal-end side wire rod  12   a  is continuously guided around the core rod  11  and is rubbed and placed onto the core rod  11 . As a result, the distal-end side wire rod  12   a  is wound around the core rod  11 . 
     The guide member  86  in the present embodiment is a pulley that is pivotably supported on an end portion of the rotator  37 . Thus, the guide member  86  is rotated while the wire rod  12  is suspended and guides the distal-end side wire rod  12   a . Therefore, it is possible to prevent occurrence of abrasion of the distal-end side wire rod  12   a  against the guide member  86  and to prevent occurrence of the surface damage of the wire rod  12  due to the abrasion. Because the wire rod  12  is wound while drawing out the core rod  11 , the distal-end side wire rod  12   a  is wound around the core rod  11  that has been drawn out from the core rod nozzle  22  in a spiral manner. 
     In the above, the core rod nozzle  22  is a cylindrical member having the inner diameter that is smaller than the outer diameter of the core rod  11  in the natural state. Because the constant tension is applied to the core rod  11  by the core rod tension device  24  ( FIG. 2 ), the relatively soft string-shaped core rod  11  is inserted through the core rod nozzle  22  in a state in which its outer diameter is reduced suitably by being pulled and is drawn out in a state in which it has a straight shape. Thus, in the vicinity of a drawing-side end portion of the core rod nozzle  22 , the core rod  11  is prevented from being bent drastically. Even if the core rod  11  is soft, as long as the winding is performed on the core rod  11  in the vicinity of the drawing-side end portion of the core rod nozzle  22 , it is possible to wind the relatively rigid wire rod  12 . Thus, with the present embodiment, the relatively rigid wire rod  12  may be wound around the relatively soft string-shaped core rod  11  in a spiral manner. 
     A proximal-end side wire rod  12   b  that extends from the wire rod nozzle  61  to the core rod  11  does not pass through between the core rod  11  and the guide member  86 , and so, it does not come into contact with the guide member  86 . As shown in  FIG. 8 , the wire rod nozzle  61  that feeds the wire rod  12  is positioned away from the core rod  11 . If the wire rod nozzle  61  is not moved in the drawing direction of the core rod  11 , the proximal-end side wire rod  12   b  between the wire rod nozzle  61  and the core rod  11  is gradually tilted along with the drawing of the core rod  11 . 
     In the present embodiment, as the core rod  11  is drawn out, the wire rod nozzle  61  from which the wire rod  12  is fed is moved by the wire-rod-nozzle moving mechanism  62  ( FIG. 3 ) in the drawing direction of the core rod  11  as shown by a broken line arrow in  FIG. 4  at the speed that is the same as a drawing speed. By moving the wire rod nozzle  61  in the drawing direction of the core rod  11  at the same speed, the intersecting angle between the proximal-end side wire rod  12   b  and the core rod  11  is kept constant. Therefore, it is possible to more stably wind the wire rod  12  in a spiral manner. 
     As shown in  FIG. 4 , after the distal-end side wire rod  12   a  that has been drawn out in advance and projected beyond the core rod  11  is wound around the core rod  11 , the rotation of the rotator  37  is stopped and further winding of the wire rod  12  is prohibited. By using the core rod drawing unit  50  ( FIG. 2 ), the core rod holding device  51  clamping the core rod  11  is moved further away from the core rod nozzle  22 , and thereby, the core rod  11  is drawn out from the core rod nozzle  22  by a length required. Thereafter, the core rod  11  is held by the core rod clamping tool  53  provided upstream of the core rod nozzle  22 , and thereby, the feeding of the core rod  11  is prohibited. In this state, the core rod  11  that has been held is released by the core rod holding device  51  of the core rod drawing unit  50 . 
     In the above, during the winding of the wire rod  12 , the core rod  11  is drawn out from the distal end of the core rod nozzle  22  in a state in which the constant tension is applied to the core rod  11 , and the outer diameter of the core rod  11  during the winding is smaller than the outer diameter of the core rod  11  in the natural state and is relatively uniform. Therefore, the wire rod  12  is wound around the core rod  11  having the smaller outer diameter and having little variation in the outer diameter in the lengthwise direction. 
     After the winding, as the core rod  11  that has been held is released by the core rod holding device  51 , the tension applied to the core rod  11  is removed. As a result, the core rod  11  returns to the natural state without the tension, and as shown in  FIG. 10 , the outer diameter of the core rod  11  is expanded. Because the wire rod  12  is wound in a spiral manner around an outer circumference of the core rod  11  having the small outer diameter, it is possible to achieve a state in which the wire rod  12  is brought into suitably close contact with an outer circumferential surface of the core rod  11  the outer diameter of which has been expanded and in which the wire rod  12  is wound in a spiral manner around the core rod  11  with substantially the same inner diameter. 
     After the winding is completed, as shown in  FIG. 9 , the wire rod  12  that has been clamped by the wire rod clamping tool  71  is released. Thereafter, the wire rod clamping tool  71  is moved away from the core rod  11  by the wire-rod-nozzle moving mechanism  62  and the retracting rod  68   a  with the wire rod nozzle  61  of the fluid pressure cylinder  68  is moved so as to project from the main body portion  68   b.    
     The length of the wire rod  12  between the core rod  11  and the wire rod nozzle  61  is set to a length that is equal to a total of the length required for the leader of the coil  8  that is precedingly formed by winding the wire rod  12  around the core rod  11  in a spiral manner and the length of the wire rod  12  required for the subsequent winding. Thereafter, the wire rod  12  is held by the wire rod clamping tool  71  again, and thereby, the movement of the wire rod  12  is prohibited. In this state, the wire rod  12  is cut by lowering the cutter device  59  by the elevating cylinder  72  and moving it into the cutting position. 
     Next, the orientation of the cutter device  59  is changed by the rotating cylinder  73 , and the cutter device  59  is moved by the wire-rod-nozzle moving mechanism  62 . By cutting the core rod  11  around which the wire rod  12  is wound in a spiral manner at a predetermined length, the coil  8  shown in  FIG. 10 , in which the wire rod  12  is wound around the core rod  11  in a spiral manner, is obtained. When the core rod  11  is cut, it is preferable that the coil  8  shown in  FIG. 10 , in which the wire rod  12  is wound around the core rod  11  in a spiral manner, be received in the recessed groove  93   a  in the receiving tool  93  by positioning the receiving tool  93  under the core rod  11  and by lifting the receiving tool  93  by the fluid pressure cylinder  92 . 
     Once the core rod  11  is cut, the coil  8  shown in  FIG. 10 , in which the wire rod  12  is wound around the core rod  11  in a spiral manner, is supported by the receiving tool  93  independently. A series of winding operation is finished by removing the coil  8  by moving the receiving tool  93  in the X axis direction from underneath the core rod nozzle  22  by the telescopic actuator  91 , and the next winding operation is started. By doing so, it is possible to consecutively obtain the coil  8  shown in  FIG. 10 , in which the wire rod  12  is wound around the core rod  11  in a spiral manner. 
     In the above-mentioned embodiment, descriptions have been given on the core-rod-holding-device moving mechanism  52  and the wire-rod-nozzle moving mechanism  62  that are configured by combining the X axis, the Y axis, and the Z axis direction telescopic actuators. However, the structures of the core-rod-holding-device moving mechanism  52  and the wire-rod-nozzle moving mechanism  62  are not limited thereto, and other structures may also be employed as long as the core rod holding device  51 , the wire rod nozzle  61 , and so forth can be moved in the three axial directions with respect to the mounting  19 . 
     In addition, in the above-mentioned embodiment, descriptions have been given on a case in which the tension bars  27  and  77  are tilted by the springs  31  and  81 , respectively, and thereby, the tension is applied to the core rod  11  and the wire rod  12  by the core rod tension device  24  and the wire rod tension device  75 , respectively. However, the structures of the core rod tension device  24  and the wire rod tension device  75  are not limited those described above, and other structures may also be employed. For example, the core rod tension device  24  and the wire rod tension device  75  may have structures in which the tension may be applied to the core rod  11  and/or the wire rod  12  by moving the core rod spool  23  and/or the wire rod spool  74  themselves/itself. 
     In addition, in the above-mentioned embodiment, a description has been given on a case in which the wire rod nozzle  61  is moved in the drawing direction of the core rod  11  at the same speed as the drawing speed when the wire rod  12  is wound. However, in a case in which the wire rod nozzle  61  feeding the wire rod  12  is sufficiently away from the core rod  11  and the tilting of the wire rod  12  caused along with the drawing of the core rod  11  may be allowed, the wire rod nozzle  61  may not necessarily be moved. 
     In addition, in the above-mentioned embodiment, a description has been given on a case in which the guide member  86  is the pulley that is pivotably supported on the end portion of the rotator  37 . However, as long as the surface damage of the wire rod  12  due to the abrasion may be avoided, the guide member  86  may be a member that is not rotatable with respect to the rotator  37 , for example, a pin shaped member in which a part coming into contact with the wire rod  12  has been polished in order to avoid the surface damage of the wire rod  12 . 
     Furthermore, in the above-mentioned embodiment, a description has been given on a case in which the core rod  11  is drawn out in straight. However, if required, during the drawing of the core rod  11 , it may be possible to draw out the core rod  11  while twisting it by rotating the core rod holding device  51  holding the core rod  11  by the motor  49 . By drawing out the core rod  11  while twisting it, it is possible to further reinforce the core rod  11  around which the wire rod  12  is wound by being rubbed and placed thereonto, and at the same time, it is possible to further increase uniformity of the outer diameter. Therefore, it becomes possible to wind the wire rod  12  around the core rod  11  in a spiral manner so as to achieve more uniform inner diameter. In a case in which it is not required to twist the core rod  11 , the motor  49  may not be installed. 
     The configurations, operations, and effects of the embodiments of the present invention will be collectively described below. 
     The coil winding apparatus is provided with: the core rod feeding unit configured to feed the string-shaped core rod from the core rod nozzle at the constant tension; the core rod drawing unit configured to draw out the core rod from the core rod nozzle against the tension by holding the core rod that has been fed from the core rod nozzle; the wire rod feeding unit configured to feed the wire rod towards the core rod that has been drawn out from the core rod nozzle in the direction intersecting therewith; the rotator into which the core rod nozzle is inserted, the rotator being capable of rotating about the core rod nozzle; the guide member provided on the end portion of the rotator with shift respect to the center of the rotator, the guide member being configured to clamp, with the core rod, the wire rod that has been fed from the wire rod feeding unit; and the rotating unit configured to rotate the rotator to rotate the guide member together with the rotator so as to revolve the wire rod around the core rod in the vicinity of the core rod nozzle. 
     The wire rod feeding unit is preferably provided with: the wire rod nozzle configured to feed the wire rod; the wire rod clamping tool configured to clamp the wire rod passing through the wire rod nozzle so as to be releasable; and an increasing/reducing unit configured to increase and reduce the gap between the wire rod nozzle and the wire rod clamping tool. The wire rod feeding unit may be further provided with the wire rod-nozzle moving mechanism configured to move at least the wire rod nozzle. The guide member is preferably the pulley pivotably supported on the end portion of the rotator, the guide member being configured such that the wire rod can be suspended. 
     The coil winding method, for winding the wire rod around the string-shaped core rod in a spiral manner, is characterized in that the core rod is inserted through the core rod nozzle while applying a predetermined tension to the core rod, and the wire rod is revolved around the core rod in the vicinity of the core rod nozzle while drawing out the core rod from the core rod nozzle against the tension. 
     It is preferable that: the wire rod be fed from the direction orthogonal to the core rod drawn out from the core rod nozzle; the wire rod be clamped by the guide member with the core rod in the vicinity of the core rod nozzle; and the guide member be rotated about the core rod, thereby the distal-end side wire rod be continuously suspended on the guide member and the distal-end side wire rod be continuously revolved around the core rod, the distal-end side wire rod being a part of the wire rod extending beyond the guide member. It is preferable that: the core rod nozzle be rotatably inserted into the rotator, and the guide member be provided on the drawing-side end portion of the rotator with shift respect to the center of the rotator; and the rotation of the guide member about the core rod be performed by rotating the rotator on which the guide member is provided. 
     It is preferable that: the proximal-end side wire rod be moved in the drawing direction of the core rod at substantially the same speed as the drawing speed of the core rod while drawing out the core rod from the core rod nozzle, the proximal-end side wire rod being a part of the wire rod not approaching the guide member. 
     With the coil winding apparatus and the coil winding method of the present embodiment, because the guide member is revolved in the vicinity of the core rod nozzle while drawing out the core rod from the core rod nozzle, the distal-end side wire rod passing through the gap between the guide member and the core rod is continuously suspended on the guide member, and the distal-end side wire rod is continuously guided to and wound around the core rod by the revolving guide member. 
     In the above, because the constant tension is applied to the core rod, the core rod is drawn out against the tension. Although the core rod is relatively soft, on a drawing end portion of the core rod nozzle, the core rod is prevented from being bent drastically. Therefore, in the vicinity of the drawing end portion of the core rod nozzle, by winding the wire rod around the core rod that has been drawn out, it becomes possible to wind the relatively rigid wire rod around the relatively soft core rod in a spiral manner. 
     When the wire rod is wound around the core rod, the core rod is drawn out from the distal end of the core rod nozzle in a state in which the constant tension is applied to the core rod. The outer diameter of the core rod during the winding of the wire rod is smaller than the outer diameter in the natural state, and so, the outer diameter of the core rod becomes relatively uniform. Thus, the wire rod is wound around the core rod having the smaller outer diameter and with little variation in the outer diameter in the lengthwise direction. 
     After the winding, when the tension applied to the core rod is released, the stretched core rod returns to the natural state to which the tension is not applied, and then, the outer diameter of the core rod is increased. Therefore, the wire rod, which is wound around the outer circumference of the core rod in a spiral manner in a state in which the outer diameter is small, comes into suitably close contact with the outer circumferential surface of the core rod the outer diameter has been increased, and a state in which the wire rod is wound around the core rod in a spiral manner with the constant inner diameter is achieved. 
     Although the embodiments of the present invention have been described in the above, the above-mentioned embodiments merely illustrate a part of application examples of the present invention, and the technical scope of the present invention is not intended to be limited to the specific configurations of the above-described embodiments. 
     This application claims priority based on Japanese Patent Application No. 2019-49389 filed with the Japan Patent Office on Mar. 18, 2019, the entire contents of which are incorporated into this specification by reference.