Abstract:
A fan apparatus comprises a stator unit, a rotor unit comprising an impeller, and a casing that houses the stator unit and the rotor unit. The casing comprise a side wall portion that surrounds a periphery of the impeller, a base portion that holds the stator unit and the rotor unit, and a plurality of connection portions that connect the side wall portion and the base portion. The casing is formed by at least two members including a first member and a second member coupled to the first member. The first member includes at least one of the connection portions and at least part of the base portion, and the second member includes at least one of the connection portions.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of Japanese Patent Application No. 2016-006160, filed Jan. 15, 2016, which is hereby incorporated by reference in its entirety. 
       BACKGROUND 
       [0002]    Technical Field 
         [0003]    The present disclosure is related to a fan apparatus and a manufacturing method of the fan apparatus. 
         [0004]    Background 
         [0005]    In a general blower (fan apparatus), a rotating body (hereinafter called a “rotor unit”) including an impeller, a yoke, a magnet, and a shaft is dynamically unbalanced due to a product error, a processing error, an assembly error or the like of the rotor unit. 
         [0006]    Therefore, a balance weight (balance adjustment weight) is attached to the rotor unit in the fan apparatus to remove the dynamic unbalance of the rotor unit (see Japanese Unexamined Patent Application Publication No. 2013-061063). 
         [0007]    For example, the balance adjustment is performed by attaching the balance weight (balance adjustment weight) to remove the dynamic unbalance of the rotor unit before the rotor unit is attached to the fan apparatus after the rotor unit is manufactured (see Japanese Unexamined Patent Application Nos. 2010-025087 and 2000-352397). 
         [0008]    However, an assembly error or the like also occurs during the assembly of the fan apparatus. Therefore, even if the balance adjustment is performed to remove the dynamic unbalance in the state in which the rotor unit is not installed, dynamic unbalance occurs in the rotor unit again after the rotor unit is assembled, depending on the assembly state of the fan apparatus. 
         [0009]    Therefore, it may be preferable to perform the balance adjustment of the rotor unit after the rotor unit is assembled to the fan apparatus. 
         [0010]    It is preferable to perform the balance adjustment of the rotor unit after the rotor unit is attached to the fan apparatus on both surfaces of an opening edge portion of a cup-shaped hub portion opening toward an upper surface of the impeller and toward a base portion. 
         [0011]    However, a casing of the fan apparatus is provided with connection portions, such as stator blades (also called fixed blades) and spokes for connecting the base portion, which holds the rotor unit and a stator unit, and a side wall portion surrounding a periphery of the impeller provided on the rotor unit. 
         [0012]    Therefore, in a small fan apparatus or the like, the connection portions and the like of the casing become an obstacle after the rotor unit is attached to the fan apparatus. There is a problem such that it is difficult to perform balance adjustment work at the opening edge portion of the hub portion of the rotor unit. 
         [0013]    The present disclosure is related to providing a fan apparatus and a manufacturing method of the fan apparatus that prevent connection portions or the like of a casing from becoming an obstacle in balance adjustment of a rotor unit. 
       SUMMARY 
       [0014]    In accordance with one aspect of the present disclosure, 
         [0000]    (1) a fan apparatus comprising: a stator unit; a rotor unit comprising an impeller; and a casing that houses the stator unit and the rotor unit, wherein the casing comprises a side wall portion that surrounds a periphery of the impeller, a base portion that holds the stator unit and the rotor unit, and a plurality of connection portions that connect the side wall portion and the base portion, the casing is formed by at least two members including a first member and a second member coupled to the first member, the first member includes at least one of the connection portions and at least part of the base portion, and the second member includes at least one of the connection portions.
 
(2) In the fan apparatus, the second member includes at least either part of the side wall portion or part of the base portion.
 
(3) In the configuration according to (2), the second member includes at least part of the side wall portion.
 
(4) In the configuration according to any one of (1) to (3), the rotor unit includes an adjustment region, on a side close to the connection portions, in which balance adjustment can be performed.
 
(5) In the configuration according to (4), the balance adjustment is performed by attaching a balance weight to the adjustment region.
 
(6) In the configuration according to (5), the rotor unit includes: a shaft; the impeller including a cup-shaped hub portion opening toward the base portion attached to the shaft and a plurality of blades on a periphery of the hub portion; a yoke provided on an inner peripheral surface of the hub portion; and a magnet provided on the yoke, and the rotor unit includes, as the adjustment region, a recess portion for attaching the balance weight provided along an opening edge portion of the hub portion.
 
(7) In the configuration according to (6), an outer diameter of the opening edge portion of the hub portion is substantially the same as an outer diameter of an end portion of the base portion closer to the hub portion.
 
(8) In the configuration according to any one of (1) to (7), the connection portion of the second member is provided with a support portion that supports lead wires on a side close to the impeller, the lead wires being drawn out from a circuit board provided between the stator unit and the base portion.
 
(9) In the configuration according to (8), the side wall portion includes a lead wire draw-out port for drawing out the lead wires to outside of the casing, and the support portion is configured to guide the lead wires to the lead wire draw-out port.
 
(10) In the configuration according to (8) or (9), the base portion is provided with a lead wire removal portion for drawing out the lead wires toward the side wall portion, and the connection portion of the second member is the connection portion adjacent to the lead wire removal portion.
 
(11) In the configuration according to (3), the side wall portion includes a lead wire draw-out port for drawing out lead wires to outside of the casing, the lead wires being drawn out from a circuit board provided between the stator unit and the base portion, said lead wire draw-out port being formed by coupling the first member and the second member.
 
(12) In the configuration according to any one of (1) to (11), a coupling point of the first member and the second member includes a coupling structure selected from a fitting structure in a stepped shape and an engaging structure engaged by an engaging hook.
 
(13) In the configuration according to any one of (1) to (12), the second member is coupled to the first member in a direction intersecting a flow of gas generated by the impeller.
 
(14) In a manufacturing method of the fan apparatus with the configuration according to any one of (1) to (13), when balance adjustment is necessary, the rotor unit is accessed from an open region provided with the second member to adjust the balance of the rotor unit before the second member is coupled to the first member in a state in which the rotor unit and the stator unit are held by the base portion.
 
         [0015]    The present disclosure can provide a fan apparatus and a manufacturing method of the fan apparatus that prevent connection portions or the like of a casing from becoming an obstacle in balance adjustment of a rotor unit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a cross-sectional view of a fan apparatus of an embodiment according to the present disclosure. 
           [0017]      FIG. 2  is a perspective view of the fan apparatus as viewed in a direction in which a base portion and connection portions of a casing of the embodiment can be easily viewed. 
           [0018]      FIG. 3  is a perspective view showing a state in which a rotor unit and a stator unit of the embodiment are held by a base portion of a first member through a bearing housing. 
           [0019]      FIG. 4  is a perspective view of the fan apparatus showing a state in which a second member is coupled to the first member shown in  FIG. 3 . 
           [0020]      FIG. 5  is a perspective view of a part inside of a casing of the second member of the embodiment. 
           [0021]      FIGS. 6A and 6B  are diagrams showing modifications of the second member of the embodiment,  FIG. 6A  showing a perspective view illustrating a first modification of the second member,  FIG. 6B  showing a perspective view illustrating a second modification of the second member. 
           [0022]      FIG. 7  is a perspective view illustrating a first modification of the fan apparatus of the embodiment according to the present disclosure. 
           [0023]      FIG. 8  is a perspective view illustrating a second modification of the fan apparatus of the embodiment according to the present disclosure. 
           [0024]      FIG. 9  is a perspective view illustrating a third modification of the fan apparatus of the embodiment according to the present disclosure. 
           [0025]      FIG. 10  is a perspective view illustrating a fourth modification of the fan apparatus of the embodiment according to the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    A mode (hereinafter called an “embodiment”) for carrying out the present disclosure will now be described in detail with reference to the attached drawings. 
         [0027]    Note that the same reference signs are provided to the same elements throughout the entire description of the embodiment. 
         [0028]      FIG. 1  is a cross-sectional view of a fan apparatus  1  of the embodiment according to the present disclosure. 
         [0029]    As shown in  FIG. 1 , the fan apparatus  1  includes: a stator unit  10 ; a rotor unit  20  including an impeller  22 ; and a casing  30  housing the stator unit  10  and the rotor unit  20 . 
       (Stator Unit) 
       [0030]    The stator unit  10  includes: a stator core  11  attached to a bearing housing  32   b;  an insulator  12  provided on the stator core  11 ; and a coil  13  wound on the stator core  11  through the insulator  12 . 
       (Rotor Unit) 
       [0031]    The rotor unit  20  includes: a shaft  21  as a rotation axis; the impeller  22  including a hub portion  22   a  attached to the shaft  21  and a plurality of blades  22   b  on a periphery of the hub portion  22   a;  a yoke  23  provided on an inner peripheral surface of the hub portion  22   a;  and a magnet  24  provided on the yoke  23 . 
         [0032]    Note that the method of attaching the hub portion  22   a  to the shaft  21  is not particularly limited. In the present embodiment, the impeller  22  is integrally molded to the shaft  21  by insert molding, and the hub portion  22   a  is attached such that the hub portion  22   a  is integrated with the shaft  21 . 
         [0033]    However, the impeller  22  provided with the hub portion  22   a  including a hole or a recess portion for inserting the shaft  21  may be created as a separate component, and the shaft  21  may be pressed or bonded into the hole or the recess portion to attach the hub portion  22   a  to the shaft  21 . 
         [0034]    The hub portion  22   a  has a cup shape opening toward a base portion  32  of the casing  30 . A recess portion  26  for attaching a balance weight  25  provided along an opening edge portion  22   aa  of the hub portion  22   a  is provided on the rotor unit  20 . 
         [0035]    Therefore, the rotor unit  20  of the present embodiment includes, on the side close to connection portions  33  of the casing  30 , the recess portion  26  (example of adjustment region) that allows performance of balance adjustment based on the balance weight  25 . The balance weight  25  is attached to the recess portion  26  to perform the balance adjustment of the rotor unit  20 . 
         [0036]    Note that a step is formed inside of the opening edge portion  22   aa  of the hub portion  22   a,  and the yoke  23  is provided as a side wall of the inside of the step to form the recess portion  26  for attaching the balance weight  25  in the present embodiment. However, the recess portion  26  may be formed on the opening edge portion  22   aa  itself of the hub portion  22   a.    
         [0037]    Although the present embodiment illustrates a case of positive balance adjustment in which the balance weight  25  is provided, the balance adjustment is not limited to the positive balance adjustment. The balance adjustment may be negative balance adjustment, in which the opening edge portion  22   aa  itself of the hub portion  22   a  of the rotor unit  20  is set as an adjustment region for performing balance adjustment, and the opening edge portion  22   aa  is scraped to perform the balance adjustment. 
         [0038]    However, although the manner of the balance adjustment will be described later, if the work of the scraping part of the rotor unit  20  is performed in a state in which the stator unit  10  and the rotor unit  20  are attached in the fan apparatus  1  as in the present embodiment, scraped debris generated by the scraping part may enter a gap or the like between the rotor unit  20  and the stator unit  10 . 
         [0039]    This causes a malfunction such as inhibited smooth rotation of the rotor unit  20 . Therefore, when the generation of the scraped debris is predicted, it is preferable to perform positive balance adjustment that does not generate the scraped debris. 
         [0040]    As shown in  FIG. 1 , an outer diameter of the opening edge portion  22   aa  of the hub portion  22   a  is substantially the same as an outer diameter of an end portion  32   a  of the base portion  32  of the casing  30  closer to the hub portion  22   a.    
         [0041]    If the outer diameter of the opening edge portion  22   aa  of the hub portion  22   a  is smaller than the outer diameter of the end portion  32   a  of the base portion  32  of the casing  30 , the base portion  32  of the casing  30  protrudes. Therefore, when the rotor unit  20  rotates, and air sucked from an upper side of  FIG. 1  flows toward a lower side of  FIG. 1 , the flow of the air is inhibited by the protrusion of the base portion  32 . 
         [0042]    On the other hand, if the outer diameter of the opening edge portion  22   aa  of the hub portion  22   a  is larger than the outer diameter of the end portion  32   a  of the base portion  32  of the casing  30 , the gap between a side wall portion  31  of the casing  30  and the opening edge portion  22   aa  becomes narrow. Not only the flow of the air is inhibited, but also small blades  22   b  must be designed. Therefore, it is difficult to obtain a favorable flow of air. 
         [0043]    Considering the above, it is preferable that the outer diameter of the opening edge portion  22   aa  of the hub portion  22   a  be substantially the same as the outer diameter of the end portion  32   a  of the base portion  32  of the casing  30  closer to the hub portion  22   a.    
       (Casing) 
       [0044]    The casing  30  includes: the side wall portion  31  surrounding a periphery of the impeller  22 ; the base portion  32 ; and the connection portions  33  including a plurality of stator blades connecting the side wall portion  31  and the base portion  32 . 
         [0045]    Note that the connection portions  33  are not limited to the stator blades, and the connection portions  33  may be spokes or the like. 
         [0046]    The bearing housing  32   b  is provided on the base portion  32 , and the stator unit  10  and the rotor unit  20  are provided on the bearing housing  32   b.    
         [0047]    Therefore, the base portion  32  is a part holding the stator unit  10  and the rotor unit  20  through the bearing housing  32   b.    
         [0048]    Although the bearing housing  32   b  is a separate component and is attached to the base portion  32  in the present embodiment, the bearing housing  32   b  may be integrally molded to the base portion  32 . 
         [0049]    Although the present embodiment illustrates a case in which the stator unit  10  is provided on the bearing housing  32   b,  the stator unit  10  may be directly held by the base portion  32 , instead of through the bearing housing  32   b.    
         [0050]    On the bearing housing  32   b,  rolling bearings  34  are provided on one end side (upper side of  FIG. 1 ) and another end side (lower side of  FIG. 1 ) in the bearing housing  32   b.  The rolling bearings  34  support the shaft  21  of the rotor unit  20  in a manner such that the shaft  21  can rotate, and the rotor unit  20  can rotate relative to the stator unit  10 . 
         [0051]    A circuit board  35  that controls the drive of the fan apparatus  1  is provided on the base portion  32 . 
         [0052]    Note that the location of the installation of the circuit board  35  is not limited to the base portion  32 , and the circuit board  35  may be provided closer to the stator core  11  of the stator unit  10 . It is only necessary that the circuit board  35  be provided between the stator unit  10  and the base portion  32 . 
         [0053]      FIG. 2  is a perspective view of the fan apparatus  1  as viewed in a direction in which the base portion  32  and the connection portion  33  of the casing  30  can be easily viewed. 
         [0054]    As shown in  FIG. 2 , the casing  30  includes at least two members including a first member  30   a  and a second member  30   b  coupled to the first member  30   a.    
         [0055]    A notch is formed on part of a peripheral side wall of the base portion  32 , and the base portion  32  is provided with a lead wire removal portion  32   c  for taking out lead wires  13   a  drawn out from the circuit board  35 , toward the side wall portion  31  of the casing  30 . The second member  30   b  includes: at least one connection portion  33  that is the connection portion  33  adjacent to the lead wire removal portion  32   c;  and at least part of the side wall portion  31 . 
         [0056]    The first member  30   a  includes the rest of the connection portions  33  of the casing  30 , the rest of the side wall portion  31 , and the base portion  32 . 
         [0057]    In the present embodiment, the first member  30   a  and the second member  30   b  are coupled at three points. 
         [0058]    Specifically, a fitting recess portion  41   a  is provided on the base portion  32  of the first member  30   a,  and a fitting protrusion portion  41   b  fitted to the fitting recess portion  41   a  is provided on the connection portion  33  of the second member  30   b.  One engaging hook  42   a  and one engaging portion  43   a  are provided on parts of the side wall portion  31  of the first member  30   a  where the side wall portion  31  of the second member  30   b  is fitted. An engaging portion  42   b  is provided on a part of the second member  30   b  corresponding to the engaging hook  42   a,  and an engaging hook  43   b  is provided on a part of the second member  30   b  corresponding to the engaging portion  43   a.    
         [0059]    Therefore, the coupling points of the first member  30   a  and the second member  30   b  include coupling structures selected from a fitting structure in a stepped shape, such as the fitting recess portion  41   a  and the fitting protrusion portion  41   b,  and an engaging structure engaged by the engaging hook  42   a  and  43   b.    
         [0060]    It is only necessary that the coupling structures be selected from the fitting structure and the locking structure. Therefore, the coupling structures may include only the locking structures, for example. 
         [0061]    The second member  30   b  is coupled to the first member  30   a  in a direction intersecting a flow of gas (hereinafter the flow of gas will be called “wind”) generated by the impeller  22 . 
         [0062]    The second member  30   b  here includes the connection portion  33  made of the stator blade, and the stator blade receives the wind generated by the impeller  22 . 
         [0063]    However, since the second member  30   b  is coupled to the first member  30   a  in the direction intersecting the wind, the second member  30   b  does not come off of the first member  30   a  even when the connection portion  33 , which is made of the stator blade, of the second member  30   b  receives the wind. 
       (Balance Adjustment) 
       [0064]    A manufacturing method involving the balance adjustment of the fan apparatus  1  of the present embodiment configured as described above will be described. 
         [0065]      FIG. 3  is a perspective view showing a state after the attachment of the stator unit  10  and the rotor unit  20  in the fan apparatus  1 , i.e., a state in which the rotor unit  20  and the stator unit  10  are held by the base portion  32  of the first member  30   a  through the bearing housing  32   b  (see  FIG. 1 ). 
         [0066]    Note that  FIG. 3  shows the fan apparatus  1  before the attachment of the second member  30   b.    
         [0067]    As can be recognized from  FIG. 3 , before the second member  30   b  is coupled to the first member  30   a  in this state, simply enabling removal of a small amount of the lead wires  13   a  drawn out from the circuit board  35  allows easy access to the recess portion  26  for attaching the balance weight  25  of the rotor unit  20  from an open region that is a location where the second member  30   b  is to be provided. 
         [0068]    Therefore, in the state in which the rotor unit  20  and the stator unit  10  are held by the base portion  32  and before the second member  30   b  is coupled to the first member  30   a,  the balance adjustment of the rotor unit  20  is performed by accessing the rotor unit  20  from the location where the second member  30   b  is to be provided. The second member  30   b  is then coupled to the first member  30   a  to manufacture the fan apparatus  1 . 
         [0069]    The balance adjustment does not have to be performed when there is no dynamic unbalance in the rotor unit  20  in the state in which the stator unit  10  and the rotor unit  20  are held by the base portion  32 . Therefore, note that the balance adjustment is carried out when the balance adjustment is necessary, and that the balance adjustment is not necessarily performed at all times. 
         [0070]      FIG. 4  is a perspective view of the fan apparatus  1  showing a state in which the second member  30   b  is coupled to the first member  30   a  shown in  FIG. 3 . 
         [0071]    In the present embodiment, a lead wire draw-out port  36  for drawing out, to the outside of the casing  30 , the lead wires  13   a  drawn out from the circuit board  35  is formed on the side wall portion  31  of the casing  30  after the coupling of the first member  30   a  and the second member  30   b.    
         [0072]    Therefore, in coupling the second member  30   b  to the first member  30   a  after the end of the balance adjustment as described above, the lead wires  13   a  are positioned at the lead wire draw-out port  36  formed by the coupling, and then the second member  30   b  is coupled to the first member  30   a.    
         [0073]    In this way, in the fan apparatus  1  of the present embodiment, the balance adjustment of the rotor unit  20  can be performed by easily accessing the recess portion  26  for attaching the balance weight  25  of the rotor unit  20  from the open region that is the location where the second member  30   b  is to be provided, before the second member  30   b  is coupled to the first member  30   a,  even in the state after the rotor unit  20  is assembled in the fan apparatus  1 . Therefore, the connection portions  33  and the like of the casing  30  do not become an obstacle in the balance adjustment of the rotor unit  20 . 
         [0074]    If there is a gap on the side wall portion  31  at the connection part of the first member  30   a  and the second member  30   b,  wind leaks from the gap. 
         [0075]    Therefore, in the present embodiment, a step  37   a  is provided at a part provided with the second member  30   b  of the first member  30   a  as shown in  FIG. 3 . 
         [0076]    A step  37   b  put together with the step  37   a  provided on the first member  30   a  is also provided on the second member  30   b  as shown in  FIG. 5  which is a perspective view of the part inside of the casing  30  of the second member  30   b.    
         [0077]    In this way, the step  37   a  and the step  37   b  overlap with each other when the second member  30   b  is coupled to the first member  30   a,  and formation of a gap on the side wall portion  31  can be prevented. 
       (Modifications of Second Member) 
       [0078]      FIGS. 6A and 6B  are diagrams showing modifications of the second member  30   b.    FIG. 6A  is a perspective view showing a first modification of the second member  30   b,  and  FIG. 6B  is a perspective view showing a second modification of the second member  30   b.    
         [0079]    As shown in  FIG. 6A , a support portion  33   a  for supporting the lead wires  13   a  (see  FIG. 3 ) on the side close to the impeller  22  (blades  22   b ) is provided on the connection portion  33  of the second member  30   b  of the first modification. 
         [0080]    The support portion  33   a  can be provided in this way to prevent part of the lead wires  13   a  from coming into contact with the blades  22   b  due to bending of the lead wires  13   a.    
         [0081]    In the second member  30   b  of the second modification of  FIG. 6B , the support portion  33   a  provided on the connection portion  33  and the connection portion  33  form a guide portion  33   b  for guiding the lead wires  13   a  to the lead wire draw-out port  36 . 
         [0082]    In this way, the support portion  33   a  is configured to guide the lead wires  13   a  to the lead wire draw-out port  36 , and the lead wires  13   a  can be surely led to the lead wire draw-out port  36 . 
         [0083]    Although the present disclosure has been described based on an embodiment, the present disclosure is not limited to this embodiment. 
         [0084]    For example, the first member  30   a  and the second member  30   b  may be configured as shown in  FIGS. 7 to 10 . 
       (Modifications of Fan Apparatus) 
       [0085]      FIG. 7  is a perspective view showing a first modification of the fan apparatus  1 .  FIG. 8  is a perspective view showing a second modification of the fan apparatus  1 .  FIG. 9  is a perspective view showing a third modification of the fan apparatus  1 .  FIG. 10  is a perspective view showing a fourth modification of the fan apparatus  1 . 
         [0086]    Note that the coupling structures (fitting structures or engaging structures) between the first member  30   a  and the second member  30   b  are not illustrated in  FIGS. 7, 8, 9, and 10 . 
         [0087]    In the first modification of the fan apparatus  1  shown in  FIG. 7 , the second member  30   b  (see hatched part) includes two connection portions  33  adjacent to the lead wire removal portion  32   c  for taking out, toward the side wall portion  31  of the casing  30 , the lead wires  13   a  drawn out from the circuit board  35 . 
         [0088]    The side wall portion  31  is cut in a length direction (a gas flow direction) at the part provided with the second member  30   b,  and the place of the side wall portion  31  of the part provided with the second member  30   b  is brought into an open state in the state before the second member  30   b  is coupled to the first member  30   a.    
         [0089]    In this way, the open region that is a location where the second member  30   b  is to be provided is further expanded, and the balance adjustment work can be more easily performed. 
         [0090]    In the second modification of the fan apparatus  1  shown in  FIG. 8 , the first member  30   a  includes only one connection portion  33  (see hatched part) connected to the base portion  32 , and the second member  30   b  includes the rest of the connection portions  33  and the entire side wall portion  31 . 
         [0091]    According to the configuration, the base portion  32  holding the stator unit  10  and the rotor unit  20  can be taken out and pulled out to the lower side of  FIG. 8 , and the balance adjustment work can be easily performed by taking out the base portion  32  in this way. 
         [0092]    In the third modification of the fan apparatus  1  shown in  FIG. 9 , the first member  30   a  (see hatched part) does not include the entire part of the base portion  32 , and both of the first member  30   a  and the second member  30   b  include part of the base portion  32 . 
         [0093]    Note that the second member  30   b  includes the connection portions  33 , the side wall portion  31 , and part of the base portion  32  in the third modification. 
         [0094]    In this way, it is only necessary that the first member  30   a  include at least one connection portion  33  and at least part of the base portion  32 . In this case, the base portion  32  holding the stator unit  10  and the rotor unit  20  can also be taken out and pulled out to the lower side of  FIG. 9 , and the balance adjustment work can be easily performed by taking out the base portion  32  in this way. 
         [0095]    In the fourth modification of the fan apparatus  1  shown in  FIG. 10 , the second member  30   b  includes one connection portion  33  (see hatched part), and the first member  30   a  includes the rest of the connection portions  33 , the side wall portion  31 , and the base portion  32 . 
         [0096]    In this case, the open region that is a location where the second member  30   b  is to be provided is also expanded by removing the second member  30   b,  and the balance adjustment work can be easily performed. 
         [0097]    Note that when the second member  30   b  is a connection portion as shown in  FIG. 10 , another connection portion  33 ′ adjacent to the lead wire removal portion  32   c  may be a second member and may be able to be removed. In this way, the open region that is a location where the second members (two second members, i.e. see the second member  30   b  and the connection portion  33 ′) are to be provided is further expanded, and the balance adjustment work can be more easily performed. 
         [0098]    Therefore, when only the connection portions are the second members, the number of second members is not limited to one, and the number of second members may be two or more. 
         [0099]    Furthermore, the second member  30   b  may be a second member including the connection portion  33 , part of the side wall portion  31 , and part of the base portion  32 , and an example of this will be simply described with reference to  FIG. 7 . Although the second member  30   b  shown in  FIG. 7  includes only the connection portion  33  and part of the side wall portion  31 , part of the base portion  32  of the point contacting the connection portion  33  may also be added to the second member  30   b.    
         [0100]    In this way, the present disclosure is not limited to the embodiment described above, and various changes can be made without departing from the scope of the present disclosure. This is apparent to those skilled in the art from the description of the claims.