Patent Publication Number: US-2023142831-A1

Title: Connector For A Linear Motor

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of the filing date under 35 U.S.C. § 119(a)-(d) of Japanese Patent Application No. 2021-181416, filed on Nov. 5, 2021. 
     FIELD OF THE INVENTION 
     The present invention relates to connectors for linear motors. More specifically, the present invention relates to a connector for connecting at least two linear motors in a series direction. 
     BACKGROUND 
     Linear motors are used in various fields, for example, semiconductor manufacturing equipment and the like. The linear motors can be used as, for example, a servomotor or the like. 
     A linear motor contains an iron core, a coil, and the like inside its body. A plurality of linear motors may be connected in a series direction to improve output. 
     In order to connect a plurality of linear motors in a series direction, an electrical connection therebetween is required. However, since an iron core, a coil, and the like are contained inside a linear motor, conventional connectors have difficulty in connecting linear motors in series due to space constraints. 
     SUMMARY 
     A linear motor connector system comprises a first linear motor, a second linear motor, and a first connector. The first connector includes a first plug holder electrically connected to the first linear motor and positioned in a recessed portion formed on an exterior face of a connecting portion of the first linear motor. The first connector further includes a first tab holder electrically connected to the second linear motor. The first tab holder is positioned in a recessed portion formed on an exterior face of a connecting portion of the second linear motor and faces the first plug holder along a direction of connection of the linear motors. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the accompanying drawings, in which: 
         FIG.  1    is a schematic diagram schematically showing connection of a plurality of linear motors; 
         FIG.  2    is a schematic diagram schematically showing connection of a plurality of linear motors (in the XZ plane); 
         FIG.  3    is a schematic diagram schematically showing connection of linear motors using connectors of the present disclosure; 
         FIG.  4    is a schematic diagram schematically showing connectors according to a first embodiment of the present disclosure; 
         FIG.  5    is a schematic diagram schematically showing (A) a housing  201   a , (B) a tab holder  101   b , and (C) a plug holder  101   a;    
         FIG.  6    is a schematic diagram schematically showing connectors according to a second embodiment of the present disclosure: 
         FIG.  7    is a schematic diagram schematically showing (A) a housing  202   a , (B) a tab holder  102   b , and (C) a plug holder  102   a;    
         FIG.  8    is a schematic diagram schematically showing connectors according to a third embodiment of the present disclosure: 
         FIG.  9    is a schematic diagram schematically showing (A) a housing  203   a , (B) a tab holder  103   b , and (C) a plug holder  103   a;    
         FIG.  10    is a schematic diagram schematically showing connectors according to a fourth embodiment of the present disclosure: 
         FIG.  11    is a schematic diagram schematically showing (A) a housing  204   a , (B) a tab holder  104   b , and (C) a plug holder  104   a;    
         FIG.  12    is a schematic diagram schematically showing connectors according to a fifth embodiment of the present disclosure: 
         FIG.  13    is a schematic diagram schematically showing (A) a housing  205   a , (B) a tab holder  105   b , and (C) a plug holder  105   a;    
         FIG.  14    is a schematic diagram schematically showing connectors according to a sixth embodiment of the present disclosure: 
         FIG.  15    is a schematic diagram schematically showing (A) a housing  206   a , (B) a tab holder  106   b , (C) a plug holder  106   a , and (D) a relay connector  106   c;    
         FIG.  16    is a schematic diagram schematically showing connectors according to a seventh embodiment of the present disclosure: 
         FIG.  17    is a schematic diagram schematically showing (A) a housing  207   a , (B) a tab holder  107   b , (C) a plug holder  107   a , and (D) a cover  107   c;    
         FIG.  18    is a schematic diagram schematically showing connectors according to an eighth embodiment of the present disclosure: 
         FIG.  19    is a schematic diagram schematically showing (A) a housing  208   a , (B) a tab holder  108   a / 108   b , and (C) a relay connector  108   c;    
         FIG.  20    is a schematic diagram schematically showing connectors according to a ninth embodiment of the present disclosure: 
         FIG.  21    is a schematic diagram schematically showing (A) a housing  209   a , (B) a tab holder  109   a / 109   b , and (C) a relay connector  109   c;    
         FIG.  22    is a schematic diagram schematically showing connectors according to a tenth embodiment of the present disclosure: 
         FIG.  23    is a schematic diagram schematically showing (A) a housing  210   a , (B) a tab holder  110   a / 110   b , and (C) a relay connector  110   c;    
         FIG.  24    is a schematic diagram schematically showing connectors according to a fourteenth embodiment of the present disclosure: 
         FIG.  25    is a schematic diagram schematically showing (A) a housing  214   a , (B) a tab holder  114   a , (C) a tab holder  114   b , and (D) a relay connector  114   c;    
         FIG.  26    is a schematic diagram schematically showing connectors according to a fifteenth embodiment of the present disclosure: 
         FIG.  27    is a schematic diagram schematically showing (A) a housing  215   a , (B) a tab holder  115   a / 115   b , and (C) a relay connector  115   c;    
         FIG.  28    is a schematic diagram schematically showing connectors according to a sixteenth embodiment of the present disclosure: 
         FIG.  29    is a schematic diagram schematically showing (A) a housing  216   a , (B) a tab holder  116   a / 116   b , (C) a relay connector  116   c , and (D) a cap  400 ; 
         FIG.  30    is a schematic diagram schematically showing electrical wires; 
         FIG.  31    is a schematic diagram schematically showing engagement between a plug holder and a tab holder; 
         FIG.  32    is a schematic diagram schematically showing a relation between a housing and a tab holder; 
         FIG.  33    is a schematic diagram schematically showing engagement between the housing and the tab holder; 
         FIG.  34    is a schematic diagram schematically showing engagement between another housing and another tab holder; 
         FIG.  35    is a schematic diagram schematically showing a relation between the plug holder and the tab holder in the sixth embodiment; 
         FIG.  36    is a schematic diagram schematically showing a relation between the plug holder, the tab holder, and the relay connector in the sixth embodiment; 
         FIG.  37    is a schematic diagram schematically showing a relation between the plug holder, the tab holder, and another relay connector in the sixth embodiment; 
         FIG.  38    is a schematic diagram schematically showing a relation between the plug holder and the tab holder in the seventh embodiment; 
         FIG.  39    is a schematic diagram schematically showing a relation between the plug holder and the tab holder in the seventh embodiment; 
         FIG.  40    is a schematic diagram schematically showing the plug holder and the tab holder in their coupled state in the seventh embodiment; 
         FIG.  41    is a schematic diagram schematically showing a relation between the plug holder, the tab holder, and the cover in the seventh embodiment; 
         FIG.  42    is a schematic diagram schematically showing a relation between two tab holders; 
         FIG.  43    is a schematic diagram schematically showing a relation between the two tab holders and a relay connector; 
         FIG.  44    is a schematic diagram schematically showing a lock mechanism of the relay connector; 
         FIG.  45    is a schematic diagram (rear view) schematically showing a relation between a housing and electrical wires; 
         FIG.  46    is a schematical diagram schematically showing a relation between the housing and a tab holder; 
         FIG.  47    is a schematic diagram schematically showing engagement between the housing and the tab holder; 
         FIG.  48    is a schematic diagram schematically showing a tab holder; 
         FIG.  49    is a schematic diagram schematically showing another tab holder; 
         FIG.  50    is a schematic diagram schematically showing a lock mechanism of a relay connector; 
         FIG.  51    is a schematic diagram schematically showing an internal structure of the relay connector; 
         FIG.  52    is a schematic diagram schematically showing caps; 
         FIG.  53    is a schematic diagram schematically showing insulating members; 
         FIG.  54    is a schematic diagram schematically showing an overmold; 
         FIG.  55    is a schematic diagram schematically showing a fourth connector; 
         FIG.  56    is a schematic diagram schematically showing a housing and a tab holder, respectively, of the fourth connector; 
         FIG.  57    is a schematic diagram schematically showing another fourth connector; 
         FIG.  58    is a schematic diagram schematically showing a housing and a tab holder, respectively, of the other fourth connector; 
         FIG.  59    is an isometric view showing an example of connectors that can be used in the sixteenth embodiment (with an overmold); 
         FIG.  60    shows an example of connectors that can be used in the sixteenth embodiment (A: a top view (without an overmold), B: a cross sectional view); 
         FIG.  61    shows the housing  216   a  of the second connector that can be used in the sixteenth embodiment (A: an isometric view, B: a front view, C: a left side view, D: a right side view, E: a rear view, F: a top view, G: a bottom view); 
         FIG.  62    shows the housing  216   a  (with electrical wires) of the second connector that can be used in the sixteenth embodiment (A: an isometric view, B: a front view, C: a left side view, D: a right side view, E: a rear view, F: a top view, G: a bottom view, H: a cross sectional view (B-B), I: a cross sectional view (A-A)); 
         FIG.  63    shows a/the tab holder  216   b / 116   a / 116   b / 316   a  that can be used in the sixteenth embodiment (A: an isometric view, B: a front view, C: a left side view, D: a right side view, E: a rear view, F: a top view, G: a bottom view, H: a cross sectional view (A-A), I: a cross sectional view (B-B), J: a cross sectional view (C-C)); 
         FIG.  64    shows the relay connector  116   c  (in an unlocked state) that can be used in the sixteenth embodiment (A: an isometric view, B: a front view, C: a left side view, D: a right side view, E: a rear view, F: a top view, G: a bottom view, H: a cross sectional view (B-B), I: a cross sectional view (A-A)); and 
         FIG.  65    shows the cap  400  that can be used in the sixteenth embodiment (A: an isometric view, B: a front view, C: a left side view, D: a right side view, E: a rear view, F: a top view, G: a bottom view). 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Exemplary embodiments of the present disclosure will be described hereinafter in detail with reference to the attached drawings, wherein like reference numerals refer to like elements. The present disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will convey the concept of the disclosure to those skilled in the art. 
     In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing. 
     An electric connector unit according to one embodiment of the present disclosure will be described in more detail below with reference to the drawings. Various elements in the drawings are just described in a schematical and exemplary manner for explaining the present disclosure, and the appearances and dimensional ratios of the elements can be different from those of real things. 
     Relative terms such as “lower”, “upper”, “horizontal”, “perpendicular”, “above”, “below”, “top”, and “bottom”, derivation terms thereof, “horizontally”, “downward”, “upward”, and the like should be understood to refer to directions as described or illustrated. In such a relative term, which is only for convenience in the explanation, an apparatus need not be configured or operated in a specific direction unless otherwise specified. Moreover, a term such as “attached”, “added”, “connected”, “coupled”, or “interconnected”, or a term similar thereto refers to a relationship in which structures are directly or indirectly fixed or attached to each other with an inclusion, attachment of both the structures which are movable or rigid, or the relationship thereof unless otherwise specified. Further, examples of the features or advantages of the present disclosure are described with reference to preferred aspects. Such aspects are sufficiently described in detail, and enable those skilled in the art to carry out the present disclosure. It should be understood that other aspects can also be used, and processes and electrical or mechanical modifications are enabled without departing from the scope of the present disclosure. Accordingly, the present disclosure is not definitely limited to preferred aspects (aspects combined with single or other features) describing examples of unrestricted combinations of conceivable features. 
     The term “generally perpendicular” as used herein need not mean “completely perpendicular”, and encompasses aspects of slight deviations therefrom (for example, an angle with respect to a winding axis is in a range of 90°±20°, for example, a range of 90°±10°). The term “generally parallel” as used herein need not mean “completely parallel”, and encompasses aspects of slight deviations therefrom (for example, a deviation from “completely parallel” is in a range of ±20°, for example, in a range of up to ±10°). 
     The present invention relates to connectors for connecting at least two linear motors in a series direction. A “linear motor” in the present disclosure generally means an electric motor without a shaft. A typical motor makes rotational motion, whereas a linear motor creates linear motion. mA direction in which a linear motor makes linear motion, for example, as indicated by the arrow of  FIG.  1   , is referred to as a “series direction” or a “direction of connection”. 
     Linear motors, theoretically, are connected in a series direction to improve output. However, since a coil, an iron core, and the like are contained inside a linear motor, there are space constraints on design. The number of linear motors connected in the series direction is not particularly limited. For example, as shown in  FIG.  1   , it is possible to connect a first linear motor LM 1 , a second linear motor LM 2 , a third linear motor LM 3  . . . in a series direction. 
     In the present disclosure, at least two linear motors can be connected in a series direction by using a connector. In particular, linear motors can be connected in a series direction at side faces of the linear motors. A “connector” in the present disclosure means a member that can provide an electrical and/or physical connection. For example, as shown in  FIG.  1   , two linear motors (LM 1 , LM 2 ) can be connected in a series direction by providing a connector  100  (referred to below as a “first connector” ( 100 )) on side faces (the XZ plane) of the two linear motors (LM 1 , LM 2 ). 
     In addition, along with the first connector  100 , a second connector  200  (referred to below as a “second connector” ( 200 )) can be provided at an end of the side face (the XZ plane) of the linear motor (LM 1 ). An electrical wire or the like may be arranged in this second connector  200  (see  FIG.  3   ). Alternatively, the second connector  200  may be used for connection to another linear motor (not shown). Along with the first connector  100 , a third connector (referred to below as a “third connector” ( 300 )) can be provided at an end portion of the side face (the XZ plane) of the linear motor (LM 2 ). The third connector  300  may be used for connection to a third linear motor LM 3 . Alternatively, an electrical wire or the like may be arranged in the third connector  300 . Regarding the arrangement of the second connector  200  and the third connector  300 , their positions may be exchanged. In other words, the positions of the second connector and the third connector may be reversed. The linear motors (LM 1 , LM 2 ) may be fixed to a plate-like table with a fastening bolt or the like. 
     In the present disclosure, connectors such as the first connector  100 , the second connector  200 , and the third connector  300  may each be composed of two or more parts (see  FIG.  3   ). The first connector  100 , the second connector  200 , and the third connector  300 , for example, as shown in  FIG.  2   , can be arranged in alignment on the side faces (the XZ plane) of the linear motors (LM 1 , LM 2 ) along the series direction indicated by the arrow. 
     Inside the linear motor LM 1 , the first connector  100  and the second connector  200  may be electrically connected by a trunk line TC 1 . It is preferred that the trunk line TC 1  be arranged along the side face or sidewall of the linear motor LM 1 . The trunk line TC 1  may be formed as a circuit on a board. By arranging the board along the side face or sidewall of the linear motor LM 1 , an internal space of the linear motor LM 1  can be efficiently used. Consequently, an improvement in space efficiency resulting from the connector arrangement can be achieved. 
     Inside the linear motor LM 2 , the first connector  100  and the third connector  300  may be electrically connected by a trunk line TC 2 . It is preferred that the trunk line TC 2  be arranged along the side face or sidewall of the linear motor LM 2 . The trunk line TC 2  may be formed as a circuit on a board. By arranging the board along the side face or sidewall of the linear motor LM 2 , an internal space of the linear motor LM 2  can be efficiently used. Consequently, an improvement in space efficiency resulting from the connector arrangement can be achieved. 
     More specifically, as shown in  FIG.  3   , the first connector  101  is composed of a plug holder  101   a  (referred to below as a “first plug holder” ( 101   a )) and a tab holder  101   b  (referred to below as a “first tab holder” ( 101   b )), the second connector  201  is composed of a housing  201   a  and a tab holder  201   b  (referred to below as a “second tab holder” ( 201   b )), and the third connector  301  is composed of, for example, a plug holder  301   a  alone. The first linear motor LM 1  and the second linear motor LM 2  can be connected in the series direction by the first connector  101 . 
     A plurality of electrical wires  120  may be arranged in the housing  201   a  of the second connector  201 . The number of electrical wires  120  arranged is not particularly limited. The plurality of electrical wires  120  can be connected to a hub connector  130 , and bundled into a single main cable  140 . The main cable  140  can be further connected to a controller  150  such as a computer (PC). The controller  150  can control the linear motors (LM 1 , LM 2 ), and also function as a power supply. 
     The third connector  301  (for example, the plug holder  301   a ) may be used for connection to the third linear motor LM 3  (not shown), or may function as an end cap. The first connector  101  (specifically, the first plug holder  101   a ) and the second connector  201  (specifically, the second tab holder  201   b ) may be electrically connected, preferably by the board, inside the first linear motor LM 1 . The first connector  101  (specifically, the first tab holder  101   b ) and the third connector  301  (specifically, the plug holder  301   a ) may be electrically connected, preferably by the board, inside the second linear motor LM 2 . 
     By making the shape of the first plug holder  101   a  and the shape of the plug holder  301   a  substantially identical to each other, for example, as shown in  FIG.  3   , in other words, by using common plug holders, connection of the linear motors can be made more efficient. In addition, by making the shape of the first tab holder  101   b  and the shape of the second tab holder  201   b  substantially identical to each other, in other words, by using common tab holders, connection of the linear motors can be made more efficient. 
     A “plug holder” in the present disclosure is a member that can be electrically connected to a trunk line (TC) that may be arranged inside a linear motor, and can form a portion of the connector together with a “tab holder” that will be described later in detail. A terminal and/or a contact and/or the like may be attached to the inside of the “plug holder”. The shape of the “plug holder” is not particularly limited, but may be, for example, a rectangular cuboid, preferably a plate-like rectangular cuboid. Material that constitutes the “plug holder” is not particularly limited. For example, it is preferred that the “plug holder” be composed of insulating plastic. The “plug holder” does not necessarily hold a plug. 
     A “tab holder” in the present disclosure is a member that can be electrically connected to a trunk line (TC) that may be arranged inside a linear motor, and can form a portion of the connector together with the above “plug holder” or with a “housing” or a “tab holder” that will be described later in detail. A terminal and/or a contact and/or the like attached to the tab holder. The shape of the “tab holder” is not particularly limited, but may be, for example, a rectangular cuboid, preferably a plate-like rectangular cuboid. Material that constitutes the “tab holder” is not particularly limited. For example, it is preferred that the “tab holder” be composed of insulating plastic. The “tab holder” does not necessarily hold a tab. 
     A “housing” in the present disclosure is a member that can be used for connection to the outside of a linear motor, in particular, for connection to an electrical wire, and can form a portion of the connector together with the above “tab holder”. A terminal and/or a contact and/or the like may be attached to the inside of the “housing”. The shape of the “housing” is not particularly limited, but may be, for example, a rectangular cuboid, preferably a plate-like rectangular cuboid. Material that constitutes the “housing” is not particularly limited. For example, it is preferred that the “housing” be composed of insulating plastic. 
     Connectors of the present disclosure will be briefly described below with reference to a first embodiment (or a concept 1) to a sixteenth embodiment (or a concept 16) thereof, and then the connectors of the present disclosure will be described in detail. 
     First Embodiment (or Concept 1) 
     Connectors according to the first embodiment (or the concept 1) are shown in  FIGS.  4  and  5   (A)- 5 (C). 
     In the first embodiment, a first connector  101  for connecting a first linear motor LM 1  and a second linear motor LM 2 , a second connector  201  for connecting six electrical wires ( 121   a  (for a main power supply) (four in number),  121   b  (for a temperature sensor) (two in number)) and the first linear motor LM 1 , and a third connector  301  (only a plug holder  301   a  is shown) connected to the second linear motor LM 2  are arranged in alignment along a series direction on side faces (the XZ plane (see  FIGS.  1  and  2   ) of the linear motors (LM 1 , LM 2 ). 
     The first connector  101  has a first plug holder  101   a  and a first tab holder  101   b . The first plug holder  101   a  and the first tab holder  101   b  are arranged facing each other along the series direction, and can be coupled by engaging them together. See  FIG.  31 (A)- 31 (C) . 
     The linear motors (LM 1 , LM 2 ) can be electrically connected together by the first plug holder  101   a  and the first tab holder  101   b.    
     The second connector  201  has a housing  201   a  and a second tab holder  201   b . The housing  201   a  and the second tab holder  201   b  are arranged facing each other along the series direction, and can be coupled by engaging them together. The electrical wires and the first linear motor LM 1  can be electrically connected together by the housing  201   a  and the second tab holder  201   b.    
     The first plug holder  101   a  and the second tab holder  201   b  may be electrically connected together inside the first linear motor LM 1 , and the first tab holder  101   b  and the plug holder  301   a  may be electrically connected together inside the second linear motor LM 2 . 
     The plug holder  101   a  may have a substantially identical shape to the plug holder  301   a , and the tab holder  101   b  may have a substantially identical shape to the second tab holder  201   b.    
     A “substantially identical shape” in the present disclosure generally means having a similar shape in terms of appearance so as to be replaceably or alternatively usable. 
     Second Embodiment (or Concept 2) 
     Connectors according to the second embodiment (or the concept 2) are shown in  FIGS.  6  and  7   (A)- 7 (C). 
     The second embodiment is characterized in that electrical wires ( 122   a  (four in number),  122   b  (two in number)) are arranged in two rows. For example, the electrical wires  122   a  are for a main power supply, and the electrical wires  122   b  are for a temperature sensor. 
     In the second embodiment, a first connector  102  for connecting a first linear motor LM 1  and a second linear motor LM 2 , a second connector  202  for connecting six electrical wires ( 122   a ,  122   b ) and the first linear motor LM 1 , and a third connector (only a plug holder  302   a  is shown) connected to the second linear motor LM 2  are arranged in alignment along a series direction on side faces of the linear motors (LM 1 , LM 2 ). 
     The first connector  102  has a first plug holder  102   a  and a first tab holder  102   b . The first plug holder  102   a  and the first tab holder  102   b  are arranged facing each other along the series direction, and can be coupled by mutual engagement. 
     The linear motors (LM 1 , LM 2 ) can be electrically connected together by the first plug holder  102   a  and the first tab holder  102   b.    
     The second connector  202  has a housing  202   a  and a second tab holder  202   b . The housing  202   a  and the second tab holder  202   b  are arranged facing each other along the series direction, and can be coupled by mutual engagement. The electrical wires and the first linear motor LM 1  can be electrically connected together by the housing  202   a  and the second tab holder  202   b.    
     The first plug holder  102   a  and the second tab holder  202   b  may be electrically connected together inside the first linear motor LM 1 , and the first tab holder  102   b  and the plug holder  302   a  may be electrically connected together inside the second linear motor LM 2 . 
     The plug holder  102   a  may have a substantially identical shape to the plug holder  302   a , and the tab holder  102   b  may have a substantially identical shape to the second tab holder  202   b.    
     Third Embodiment (Concept 3) 
     Connectors according to the third embodiment are shown in  FIGS.  8  and  9   (A)- 9 (C). 
     The third embodiment is similar to the first embodiment, but designed for lower voltage (for example, the first embodiment for 500 V, the third embodiment for 250V). 
     In the third embodiment, a first connector  103  for connecting a first linear motor LM 1  and a second linear motor LM 2 , a second connector  203  for connecting six electrical wires ( 121   a  (four in number),  121   b  (two in number)) and the first linear motor LM 1 , and a third connector (only a plug holder  303   a  is shown) connected to the second linear motor LM 2  are arranged in alignment along a series direction on side faces of the linear motors (LM 1 , LM 2 ). 
     The first connector  103  has a first plug holder  103   a  and a first tab holder  103   b . The first plug holder  103   a  and the first tab holder  103   b  are arranged facing each other along the series direction, and can be coupled by mutual engagement. 
     The linear motors (LM 1 , LM 2 ) can be electrically connected together by the first plug holder  103   a  and the first tab holder  103   b.    
     The second connector  203  has a housing  203   a  and a second tab holder  203   b . The housing  203   a  and the second tab holder  203   b  are arranged facing each other along the series direction, and can be coupled by mutual engagement. The electrical wires and the first linear motor LM 1  can be electrically connected together by the housing  203   a  and the second tab holder  203   b.    
     The first plug holder  103   a  and the second tab holder  203   b  may be electrically connected together inside the first linear motor LM 1 , and the first tab holder  103   b  and the plug holder  303   a  may be electrically connected together inside the second linear motor LM 2 . 
     The plug holder  103   a  may have a substantially identical shape to the plug holder  303   a , and the tab holder  103   b  may have a substantially identical shape to the second tab holder  203   b.    
     Fourth Embodiment (or Concept 4) 
     Connectors according to the fourth embodiment (or the concept 4) are shown in  FIGS.  10  and  11   (A)- 11 (C). 
     In the fourth embodiment, a first connector  104  for connecting a first linear motor LM 1  and a second linear motor LM 2 , a second connector  204  for connecting six electrical wires ( 121   a  (for a main power supply) (four in number),  121   b  (for a temperature sensor) (two in number)) and the first linear motor LM 1 , and a third connector (only a plug holder  304   a  is shown) connected to the second linear motor LM 2  are arranged in alignment along a series direction on side faces of the linear motors (LM 1 , LM 2 ). 
     The first connector  104  has a first plug holder  104   a  and a first tab holder  104   b . The first plug holder  104   a  and the first tab holder  104   b  are arranged facing each other along the series direction, and can be coupled by mating them together. 
     The linear motors (LM 1 , LM 2 ) can be electrically connected together by the first plug holder  104   a  and the first tab holder  104   b.    
     The second connector  204  has a housing  204   a  and a second tab holder  204   b . The housing  204   a  and the second tab holder  204   b  are arranged facing each other along the series direction, and can be coupled by mutual engagement. The electrical wires and the first linear motor LM 1  can be electrically connected together by the housing  204   a  and the second tab holder  204   b.    
     The first plug holder  104   a  and the second tab holder  204   b  may be electrically connected together inside the first linear motor LM 1 , and the first tab holder  104   b  and the plug holder  304   a  may be electrically connected together inside the second linear motor LM 2 . 
     The plug holder  104   a  may have a substantially identical shape to the plug holder  304   a , and the tab holder  104   b  may have a substantially identical shape to the second tab holder  204   b.    
     Fifth Embodiment (or Concept 5) 
     Connectors according to the fifth embodiment (or the concept 5) are shown in  FIGS.  12  and  13   (A)- 13 (C). 
     The fifth embodiment is similar to the fourth embodiment, but designed for lower voltage (for example, the fourth embodiment for 500V, the fifth embodiment for 250V). 
     In the fifth embodiment, a first connector  105  for connecting a first linear motor LM 1  and a second linear motor LM 2 , a second connector  205  for connecting six electrical wires ( 121   a  (for a main power supply) (four in number),  121   b  (for a temperature sensor) (two in number)) and the first linear motor LM 1 , and a third connector (only a plug holder  305   a  is shown) connected to the second linear motor LM 2  are arranged in alignment along a series direction on side faces of the linear motors (LM 1 , LM 2 ). 
     The first connector  105  has a first plug holder  105   a  and a first tab holder  105   b . The first plug holder  105   a  and the first tab holder  105   b  are arranged facing each other along the series direction and can be coupled by mating them together. The linear motors (LM 1 , LM 2 ) can be electrically connected together by the first plug holder  105   a  and the first tab holder  105   b.    
     The second connector  105  has a housing  205   a  and a second tab holder  205   b . The housing  205   a  and the second tab holder  205   b  are arranged facing each other along the series direction, and can be coupled by engaging them together. The electrical wires and the first linear motor LM 1  can be electrically connected together by the housing  205   a  and the second tab holder  205   b.    
     The first plug holder  105   a  and the second tab holder  205   b  may be electrically connected together inside the first linear motor LM 1 , and the first tab holder  105   b  and the plug holder  305   a  may be electrically connected together inside the second linear motor LM 2 . 
     The plug holder  105   a  may have a substantially identical shape to the plug holder  305   a , and the tab holder  105   b  may have a substantially identical shape to the second tab holder  205   b.    
     Sixth Embodiment (or Concept 6) 
     Connectors according to the sixth embodiment (or the concept 6) are shown in  FIGS.  14  and  15   (A)- 15 (D). 
     In the sixth embodiment, a first connector  106  for connecting a first linear motor LM 1  and a second linear motor LM 2 , a second connector  206  for connecting six electrical wires ( 123 ) and the first linear motor LM 1 , a third connector (only a plug holder  306   a  is shown) connected to the second linear motor LM 2  are arranged in alignment along a series direction on side faces of the linear motors (LM 1 , LM 2 ). 
     The first connector  106  has a first plug holder  106   a , a first tab holder  106   b , and a relay connector  106   c  (see  FIG.  15 (D) ). The first plug holder  106   a  and the first tab holder  106   b  are arranged facing each other along the series direction, and can be coupled by engaging both of them with the relay connector  106   c  (see  FIG.  15 (D) ) (see  FIGS.  35  to  36   ). The first plug holder  106   a  and the first tab holder  106   b  can electrically connect the linear motors (LM 1 , LM 2 ) together via the relay connector  106   c  (see  FIG.  15 (D) ). 
     The second connector  206  has a housing  206   a  and a second tab holder  206   b . The housing  206   a  and the second tab holder  206   b  are arranged facing each other along the series direction, and can be coupled by engaging them together. The electrical wires and the first linear motor LM 1  can be electrically connected together by the housing  206   a  and the second tab holder  206   b.    
     The first plug holder  106   a  and the second tab holder  206   b  may be electrically connected together inside the first linear motor LM 1 , and the first tab holder  106   b  and the plug holder  306   a  may be electrically connected together inside the second linear motor LM 2 . 
     The plug holder  106   a  may have a substantially identical shape to the plug holder  306   a , and the tab holder  106   b  may have a substantially identical shape to the second tab holder  206   b.    
     Seventh Embodiment (or Concept 7) 
     Connectors according to the seventh embodiment (or the concept 7) are shown in  FIGS.  16  and  17   (A)- 17 (D). 
     A first connector  107  for connecting a first linear motor LM 1  and a second linear motor LM 2 , a second connector  207  for connecting six electrical wires ( 123 ) and the first linear motor LM 1 , and a third connector (only a plug holder  307   a  is shown) connected to the second linear motor LM 2  may be arranged in alignment along a series direction on side faces of the linear motors (LM 1 , LM 2 ). 
     The first connector  107  has a first plug holder  107   a , a first tab holder  107   b , and a cover  107   c  (see  FIG.  17 (D) ). The first plug holder  107   a  and the first tab holder  107   b  are arranged facing each other, and can be coupled by engaging them together (see  FIGS.  38  to  41   ). The linear motors (LM 1 , LM 2 ) can be electrically connected together by the first plug holder  107   a  and the first tab holder  107   b.    
     The first plug holder  107   a  and the first tab holder  107   b  may each have a hole such as a threaded hole, through which the cover  107   c  (see  FIG.  17 (D) ) can be fixed thereto with a fastener such as a screw. 
     The connector  207  has a housing  207   a  and a second tab holder  207   b . The housing  207   a  and the second tab holder  207   b  are arranged facing each other along the series direction, and can be coupled by engaging them together. The electrical wires and the first linear motor LM 1  can be electrically connected together by the housing  207   a  and the second tab holder  207   b.    
     The first plug holder  107   a  and the second tab holder  207   b  may be electrically connected together inside the first linear motor LM 1 , and the first tab holder  107   b  and the plug holder  307   a  may be electrically connected together inside the second linear motor LM 2 . 
     The plug holder  107   a  may have a substantially identical shape to the plug holder  307   a , and the tab holder  107   b  may have a substantially identical shape to the second tab holder  207   b.    
     Eighth Embodiment (or Concept 8) 
     Connectors according to the eighth embodiment (or the concept 8) are shown in  FIGS.  18  and  19   (A)- 19 (C). 
     In the eighth embodiment, a first connector  108  for connecting a first linear motor LM 1  and a second linear motor LM 2 , a second connector  208  for connecting four electrical wires ( 124 ) and the first linear motor LM 1 , and a third connector (only a tab holder  308   a  is shown) connected to the second linear motor LM 2  may be arranged in alignment along a series direction on side faces of the linear motors (LM 1 , LM 2 ). 
     The first connector  108  has two identically-shaped tab holders ( 108   a ,  108   b ) (see  FIG.  19 (B) ) and a relay connector  108   c  (see  FIG.  19 (C) ). The two tab holders ( 108   a ,  108   b ) are arranged facing each other along the series direction, and can be coupled by engaging them with the relay connector  108   c . The two tab holders ( 108   a ,  108   b ) can electrically connect the linear motors (LM 1 , LM 2 ) together via the relay connector  108   c . The relay connector  108   c  includes a slide plate  108   d  having a lock mechanism (see  FIGS.  42  to  44   ). 
     The second connector  208  has a housing  208   a  and a second tab holder  208   b . The housing  208   a  and the second tab holder  208   b  are arranged facing each other along the series direction, and can be coupled by engaging them together. The electrical wires and the first linear motor LM 1  can be electrically connected together by the housing  208   a  and the second tab holder  208   b.    
     The tab holder  108   a  and the second tab holder  208   b  may be electrically connected together inside the first linear motor LM 1 , and the tab holder  108   b  and the tab holder  208   b  may be electrically connected together inside the second linear motor LM 2 . 
     The tab holder  108   a  may have a substantially shape to the tab holder  308   a , and the tab holder  108   b  may have a substantially shape to the second tab holder  208   b.    
     Ninth Embodiment (or Concept 9) 
     Connectors according to the ninth embodiment (or the concept 9) are shown in  FIGS.  20  and  21   (A)- 21 (C). 
     The ninth embodiment is similar to the eighth embodiment, but designed for lower voltage (for example, the eighth embodiment for 500V, the ninth embodiment for 250V). They also have different numbers of electrical wires used. 
     In the ninth embodiment, a first connector  109  for connecting a first linear motor LM 1  and a second linear motor LM 2 , a second connector  209  for connecting six electrical wires ( 123 ) and the first linear motor LM 1 , and a third connector (only a tab holder  309   a  is shown) connected to the second linear motor LM 2  may be arranged in alignment along a series direction on side faces of the linear motors (LM 1 , LM 2 ). 
     The first connector  109  has two identically-shaped tab holders ( 109   a ,  109   b ) (see  FIG.  21 (B) ) and a relay connector  109   c  (see  FIG.  21 (C) ). The two tab holders ( 109   a ,  109   b ) are arranged facing each other along the series direction, and can be coupled by engaging them with the relay connector  109   c . The two tab holders ( 109   a ,  109   b ) can electrically connect the linear motors (LM 1 , LM 2 ) together via the relay connector  109   c . The relay connector  109   c  includes a slide plate having a lock mechanism. See  FIGS.  42 - 44   (B),  50 (A) and  50 (B), and  51 (A) and  51 (B). 
     The second connector  209  has a housing  209   a  and a second tab holder  209   b . The housing  209   a  and the second tab holder  209   b  are arranged facing each other along the series direction, and can be coupled by engaging them together. The electrical wires and the first linear motor LM 1  can be electrically connected together by the housing  209   a  and the second tab holder  209   b.    
     The tab holder  109   a  and the second tab holder  209   b  may be electrically connected together inside the first linear motor LM 1 , and the tab holder  109   b  and the tab holder  309   a  may be electrically connected together inside the second linear motor LM 2 . 
     The tab holder  109   a  may have a substantially identical shape to the tab holder  309   a , and the tab holder  109   b  may have a substantially identical shape to the second tab holder  209   b.    
     Tenth Embodiment (or Concept 10) 
     Connectors according to the tenth embodiment (or the concept 10) are shown in  FIGS.  22  and  23   (A)- 23 (C). 
     The tenth embodiment is similar to the ninth embodiment, but has a different number of electrical wires used. 
     In the tenth embodiment, a first connector  110  for connecting a first linear motor LM 1  and a second linear motor LM 2 , a second connector  210  for connecting four electrical wires ( 124 ) and the first linear motor LM 1 , and a third connector (only a tab holder  310   a  is shown) connected to the second linear motor LM 2  may be arranged in alignment along a series direction on side faces of the linear motors (LM 1 , LM 2 ). 
     The first connector  110  has two identically-shaped tab holders ( 110   a ,  110   b ) (see  FIG.  23 (B) ) and a relay connector  110   c  (see  FIG.  23 (C) ). The two tab holders ( 110   a ,  110   b ) are arranged facing each other along the series direction, and can be coupled by engaging them with the relay connector  110   c . The two tab holders ( 110   a ,  110   b ) can electrically connect the linear motors (LM 1 , LM 2 ) together via the relay connector  110   c . The relay connector  110   c  includes a slide plate having a lock mechanism. See  FIGS.  42 - 44 ,  50  and  51   ) 
     The second connector  210  has a housing  210   a  and a second tab holder  210   b . The housing  210   a  and the second tab holder  210   b  are arranged facing each other along the series direction, and can be coupled by engaging them together. The electrical wires and the first linear motor LM 1  can be electrically connected together by the housing  210   a  and the second tab holder  210   b.    
     The tab holder  110   a  and the second tab holder  210   b  may be electrically connected together inside the first linear motor LM 1 , and the tab holder  110   b  and the tab holder  310   a  may be electrically connected together inside the second linear motor LM 2 . 
     The tab holder  110   a  may have a substantially identical shape to the tab holder  310   a , and the tab holder  110   b  may have a substantially identical shape to the second tab holder  210   b.    
     Eleventh Embodiment (or Concept 11) 
     In the eleventh embodiment, a first connector for connecting a first linear motor and a second linear motor, a second connector for connecting six electrical wires and the first linear motor, and a third connector connected to the second linear motor are arranged in alignment along a series direction on side faces of the linear motors. 
     The first connector has two differently-shaped tab holders and a relay connector. The two tab holders are arranged facing each other along the series direction, and can be coupled by engaging them with the relay connector. The two tab holders can electrically connect the linear motors together via the relay connector. The relay connector includes a slide plate having a lock mechanism. See  FIGS.  42  to  44   (B),  50 (A) and  50 (B), and  51 (A) and  51 (B). 
     The second connector has a housing and a second tab holder. The housing and the second tab holder are arranged facing each other along the series direction, and can be coupled by engaging them together. The electrical wires and the first linear motor can be electrically connected together by the housing and the second tab holder. The housing has an engaging portion for engaging with the second tab holder. See  FIGS.  45 - 47   (B). 
     The tab holder and the second tab holder may be electrically connected together inside the first linear motor, and one of the tab holders and the third connector may be electrically connected together inside the second linear motor. It should be noted that the tab holders extending in the same direction may have substantially identical shapes. 
     Twelfth Embodiment (or Concept 12) 
     In the twelfth embodiment, a first connector for connecting a first linear motor and a second linear motor, a second connector for connecting six electrical wires and the first linear motor, and a third connector connected to the second linear motor may be arranged in alignment along a series direction on side faces of the linear motors. 
     The first connector has two differently-shaped tab holders and a relay connector. The two tab holders are arranged facing each other along the series direction, and can be coupled by engaging them with the relay connector. The two tab holders can electrically connect the linear motors together via the relay connector. The relay connector includes a slide plate having a lock mechanism. See  FIGS.  42 - 44   (B),  50 (A) and  50 (B), and  51 (A) and  51 (B). 
     The second connector has a housing and a second tab holder. The housing and the second tab holder are arranged facing each other along the series direction, and can be coupled by engaging them together. The electrical wires and the first linear motor can be electrically connected together by the housing and the second tab holder. The housing has an engaging portion for engaging with the second tab holder. 
     One of the two tab holders and the second tab holder may be electrically connected together inside the first linear motor, or the two tab holders may be electrically connected together inside the second linear motor. The tab holders extending in the same direction may have substantially identical shapes. The twelfth embodiment is characterized in that the two tab holders each have a through-hole (one in number) for attachment to a board. 
     Thirteenth Embodiment (or Concept 13) 
     In the thirteenth embodiment, a first connector for connecting a first linear motor and a second linear motor, a second connector for connecting four electrical wires and the first linear motor, and a third connector connected to the second linear motor may be arranged in alignment along a series direction on side faces of the linear motors. 
     The first connector has two identically-shaped tab holders and a relay connector. The two tab holders are arranged facing each other along the series direction, and can be coupled by engaging them with the relay connector. The two tab holders can electrically connect the linear motors together via the relay connector. The relay connector includes a slide plate having a lock mechanism. See  FIGS.  44 ,  50 , and  51   . 
     The second connector has a housing and a second tab holder. The housing and the second tab holder are arranged facing each other along the series direction, and can be coupled by mutual engagement. The electrical wires and the first linear motor can be electrically connected together by the housing and the second tab holder. The housing has an engaging portion for engaging with the tab holder. 
     The tab holder and the second tab holder may be electrically connected together inside the first linear motor, or the two tab holders may be electrically connected together inside the second linear motor. The tab holders extending in the same direction may have substantially identical shapes. The thirteenth embodiment is characterized in that the two tab holders each have through-holes (two in number) for attachment to a board. 
     Fourteenth Embodiment (or Concept 14) 
     Connectors according to the fourteenth embodiment (or the concept 14) are shown in  FIGS.  24  and  25   (A)- 25 (D). 
     In the fourteenth embodiment, a first connector  114  for connecting a first linear motor LM 1  and a second linear motor LM 2 , a second connector  214  for connecting six electrical wires ( 121   a  (four in number),  121   b  (two in number)) and the first linear motor LM 1 , and a third connector (only a tab holder  314   a  is shown) connected to the second linear motor LM 2  may be arranged in alignment along a series direction on side faces of the linear motors (LM 1 , LM 2 ). 
     The first connector  114  has two differently-shaped tab holders ( 114   a ,  114   b ) (see  FIGS.  25 (B) and  25 (C) ) and a relay connector  114   c  (see  FIG.  25 (D) ). The two tab holders ( 114   a ,  114   b ) are arranged facing each other along the series direction, and can be coupled by engaging them with the relay connector  114   c . The two tab holders ( 114   a ,  114   b ) can electrically connect the linear motors (LM 1 , LM 2 ) together via the relay connector  114   c . The relay connector  114   c  includes a slide plate having a lock mechanism. See  FIGS.  42 - 44   (B),  50 (A) and  50 (B), and  51 (A) and  51 (B). 
     The second connector  214  has a housing  214   a  and a second tab holder  214   b . The housing  214   a  and the second tab holder  214   b  are arranged facing each other along the series direction, and can be coupled by engaging them together. The electrical wires and the first linear motor LM 1  can be electrically connected together by the housing  214   a  and the second tab holder  214   b . The housing  214   a  has an engaging portion for engaging with the second tab holder  214   b.    
     The tab holder  114   a  and the second tab holder  214   b  may be electrically connected together inside the first linear motor LM 1 , and the tab holder  114   b  and the tab holder  314   a  may be electrically connected together inside the second linear motor LM 2 . 
     The tab holder  114   a  may have a substantially identical shape to the tab holder  314   a , and the tab holder  114   b  may have a substantially identical shape to the second tab holder  214   b.    
     The fourteenth embodiment is characterized in that the two tab holders ( 114   a ,  114   b ) each have through-holes (two in number) for attachment to a board. 
     Fifteenth Embodiment (or Concept 15) 
     Connectors according to the fifteenth embodiment (or the concept 15) are shown in  FIGS.  26  and  27   (A)- 27 (C). 
     In the fifteenth embodiment, a first connector  115  for connecting a first linear motor LM 1  and a second linear motor LM 2 , a second connector  215  for connecting four electrical wires ( 124 ) and the first linear motor LM 1 , and a third connector (only a tab holder  315   a  is shown) connected to the second linear motor LM 2  may be arranged in alignment along a series direction on side faces of the linear motors (LM 1 , LM 2 ). 
     The first connector  115  has two identically-shaped tab holders ( 115   a ,  115   b ) (see  FIG.  27 (B) ) and a relay connector  115   c  (see  FIG.  27 (C) ). The two tab holders ( 115   a ,  115   b ) are arranged facing each other along the series direction, and can be coupled by engaging them with the relay connector  115   c . The two tab holders ( 115   a ,  115   b ) can electrically connect the linear motors (LM 1 , LM 2 ) together via the relay connector  115   c . The relay connector  115   c  includes a slide plate having a lock mechanism. See  FIGS.  42 - 44   (B),  50 (A) and  50 (B), and  51 (A) and  51 (B). 
     The second connector  215  has a housing  215   a  and a second tab holder  215   b . The housing  215   a  and the second tab holder  215   b  are arranged facing each other along the series direction, and can be coupled by engaging them together. The electrical wires and the first linear motor LM 1  can be electrically connected together by the housing  215   a  and the second tab holder  215   b . The housing  215   a  has an engaging portion for engaging with the second tab holder  215   b.    
     The tab holder  115   a  and the second tab holder  215   b  may be electrically connected together inside the first linear motor LM 1 , and the tab holder  115   b  and the tab holder  315   a  may be electrically connected together inside the second linear motor LM 2 . 
     The tab holder  115   a  may have a substantially identical shape to the tab holder  315   a , and the tab holder  115   b  may have a substantially identical shape to the second tab holder  215   b.    
     The fifteenth embodiment is characterized in that the two tab holders ( 115   a ,  115   b ) each have through-holes (two in number) for attachment to a board. 
     Sixteenth Embodiment (or Concept 16) 
     Connectors according to the sixteenth embodiment (or the concept 16) are shown in  FIGS.  28  and  29   (A)- 29 (D). 
     In the sixteenth embodiment, a first connector  116  for connecting a first linear motor LM 1  and a second linear motor LM 2 , a second connector  216  for connecting four electrical wires ( 124 ) and the first linear motor LM 1 , and a third connector (only a tab holder  316   a  is shown) connected to the second linear motor LM 2  may be arranged in alignment along a series direction on side faces of the linear motors (LM 1 , LM 2 ). 
     The first connector  116  has two identically-shaped tab holders ( 116   a ,  116   b ) (see  FIG.  29 (B) ) and a relay connector  116   c  (see  FIG.  29 (C) ). The two tab holders ( 116   a ,  116   b ) are arranged facing each other along the series direction, and can be coupled by engaging them with the relay connector  116   c . The two tab holders ( 116   a ,  116   b ) can electrically connect the linear motors (LM 1 , LM 2 ) together via the relay connector  116   c . The relay connector  116   c  includes a slide plate having a lock mechanism. See  FIGS.  42 - 44   (B),  50 (A) and  50 (B), and  51 (A) and  51 (B). 
     The second connector  216  has a housing  216   a  and a second tab holder  216   b . The housing  216   a  and the second tab holder  216   b  are arranged facing each other along the series direction, and can be coupled by engaging together. The electrical wires and the first linear motor LM 1  can be electrically connected together by the housing  216   a  and the second tab holder  216   b . The housing  216   a  has an engaging portion for engaging with the second tab holder  216   b.    
     The tab holder  116   a  and the second tab holder  216   b  may be electrically connected together inside the first linear motor LM 1 , and the tab holder  116   b  and the tab holder  316   a  may be electrically connected together inside the second linear motor LM 2 . 
     The tab holder  116   a  may have a substantially identical shape to the tab holder  316   a , and the tab holder  116   b  may have a substantially identical shape to the tab holder  216   b.    
     The sixteenth embodiment is characterized in that the two tab holders ( 116   a ,  116   b ) each have through-holes (two in number) for attachment to a board. 
     A “first connector” ( 100  to  116 ), a “second connector” ( 200  to  216 ), and a “third connector” ( 300  to  316 ) will each be described below in detail. 
     &lt;First Connector&gt; 
     A first connector (for example, the connectors  100  to  116 ) is a connector for connecting at least two linear motors (LM 1 , LM 2 ) in a series direction (see  FIGS.  1  and  2   ). 
     For example, the first connector (for example, the connectors  101  to  105 ) may include a first plug holder (for example, the plug holders  101   a  to  105   a ) and a first tab holder (for example, the tab holders  101   b  to  105   b ). See  FIGS.  4 - 13   (C). 
     The first plug holder and the first tab holder may face each other along a direction of connection of the linear motors (LM 1 , LM 2 ). 
     The first plug holder and the first tab holder may be positioned in a recessed portion provided in side faces (the XZ plane) of connecting portions of the two linear motors (LM 1 , LM 2 ). 
     The first plug holder may be configured to be attachable to the first linear motor (LM 1 ). 
     The first tab holder may be configured to be attachable to the second linear motor (LM 2 ). 
     By connecting the first plug holder and the first tab holder, for example, electrically and/or physically, the first linear motor (LM 1 ) and the second linear motor (LM 2 ) can be connected, for example, electrically and/or physically. 
     A recessed portion that may be provided in side faces (the XZ plane) of connecting portions of two linear motors means a recessed portion that may be formed by combining two separate facing spaces that may be provided in the bodies of the linear motors. 
     A space S 1  and/or a space S 2  may each have a plate-like rectangular cubic shape. The space S 1  and the space S 2  may have identical or different shapes. 
     Regarding the space S 1  and/or the space S 2 , their positions in the Z-axis direction are not particular limited. 
     The space S 1  and/or the space S 2  can be positioned in the side face (the XZ plane) of the linear motor, and it is preferred that the space S 1  and/or the space S 2  be positioned at an end portion thereof in a direction of movement of the linear motor. 
     The linear motor, specifically the body of the linear motor, basically, contains an iron core and a coil. Inside the linear motor, a board, for example, a printed circuit board or the like, may be positioned. The board may be positioned between the spaces S 1  and S 2  along the side face (the XZ plane) or sidewall of the linear motor. At least a portion of the linear motor may be formed by an overmold. In particular, at least a portion of the side face (the XZ plane) of the linear motor may be formed by an overmold. 
     The plug holder and/or the tab holder can be positioned in the space S 1  and/or the space S 2 , and the plug holder and/or the tab holder can be electrically connected to the board. 
     In the present disclosure, the plug holder and/or the tab holder may be electrically connected not by using the board but by, for example, an electrical wire, a conductive wire, or the like, as a trunk line. 
     In the present disclosure, wiring or a circuit that may be formed inside a linear motor may also be referred to as a trunk line (TC) (see  FIG.  2   ). 
     The first connector, for example, the first plug holder and the first tab holder, may be positioned substantially flush with the side face or the sidewall of the linear motor. See  FIGS.  4  to  29   (D). 
     “Substantially flush” in the present disclosure means that a connector is arranged in a recessed portion or a space that may be provided in a linear motor without prominently rising or protruding from a face constituting the linear motor, in other words, without prominently rising or protruding in a direction perpendicular to a series direction or a direction of movement or a direction of connection of linear motors. 
     The connector may be buried by 80% or more, preferably 90% or more, more preferably 95% or more, of its volume in the recessed portion that may be provided in the linear motor. 
     The connector may be raised or protruded by, for example, 20% or more, preferably 10% or more, more preferably 5% or more, of its thickness, on a length basis, from the recessed portion that may be provided in the linear motor. 
     It is particularly preferred that the connector be arranged in the recessed portion that may be provided in the linear motor such that the connector has a surface flush with a face constituting the linear motor. The connector may be completely buried in the recessed portion that may be provided in the linear motor. 
     By positioning the first plug holder and the first tab holder substantially flush with the side faces of the linear motors, the possibility is significantly reduced that the first plug holder and the first tab holder may interfere with motion in the series direction or the direction of movement or the direction of connection of the linear motors. 
     At least a portion of the first plug holder may be inserted into a portion of the first tab holder. See  FIGS.  4 - 13   (C). Alternatively, at least a portion of the first tab holder may be inserted into a portion of the first plug holder. 
     The first plug holder and/or the first tab holder may have a protruding portion and/or a recessed portion formed so as to serve as a guide for the insertion. 
     By inserting at least a portion of the first plug holder into a portion of the first tab holder (see  FIGS.  4 - 13   (C)) and/or inserting at least a portion of the first tab holder into a portion of the first plug holder, their electrical and/or physical connection can be more reliably formed. 
     An engaging portion provided to the first plug holder and an engaging portion provided to the first tab holder may be coupled together. See  FIGS.  4 - 9   (C). 
     Taking as an example the first plug holder  101   a  and the first tab holder  101   b  of the first connector  101  shown in  FIGS.  4  and  5   (A)- 5 (C), their engaging portions will be described in detail with reference to  FIGS.  31 (A)- 31 (C) . 
       FIG.  31 (A)  shows an engaged and coupled state of the first plug holder  101   a  and the first tab holder  101   b  of the first connector  101 . 
       FIG.  31 (B)  illustrates internal structures of the first plug holder  101   a  and the first tab holder  101   b.    
     The first plug holder  101   a  may have a space S 3  provided therein that can accommodate, for example, electrical wires (see  FIG.  45   ) (see  FIG.  31 (B) ). 
     By coupling the first plug holder  101   a  and the first tab holder  101   b , a terminal T 4  provided in the first tab holder  101   b  may be inserted and positioned into the first plug holder  101   a.    
     Inside the first plug holder  101   a , a terminal T 3  and the terminal T 4  of the first tab holder  101   b  may contact each other, thereby forming electrical contact, in other words, an electrical contact point. 
     Inside the first plug holder  101   a , the terminal T 3  may be connected to the electrical wire (not shown) or a trunk line (not shown). 
     As shown in  FIG.  31 (B) , the first plug holder  101   a  has an engaging portion E 1 , and the first tab holder  101   b  has an engaging portion E 2 . The engaging portion E 1  and the engaging portion E 2  may be configured to be engaged with and caught on each other. The shapes of the engaging portion E 1  and the engaging portion E 2  are not particularly limited. Locations at which the engaging portion E 1  and the engaging portion E 2  may be formed are not particularly limited, either. 
     The terminal T 4  of the first tab holder  101   b  may be electrically connected to the board by soldering, and the board can be arranged in the linear motor. 
     The first tab holder  101   b  may have a protruding portion (specifically a boss) as an engaging portion E 3  for engaging with a board P, and may have a protruding portion (specifically a rib) as an engaging portion E 4 , on a portion (a bottom portion) thereof that may face the board P (see  FIG.  31 (C) ). The shapes of the engaging portion E 3  and the engaging portion E 4  are not particularly limited. The board P may have a through-hole formed therein for receiving the engaging portion E 3  or the like (see  FIG.  31 (B) ). 
     Since the first plug holder and/or the first tab holder have their respective engaging portions, the first plug holder and/or the first tab holder can be prevented from being disengaged, thus forming an electrical and/or physical connection more reliably. 
     The first plug holder and the first tab holder do not have to be directly electrically connected. In this case, the first connector may further include a relay connector for electrically connecting the first plug holder and the first tab holder. See  FIGS.  14 - 15   (D) and  35 - 36 . 
     Regarding the first connector ( 106 ) shown in  FIGS.  14 - 15   (D), for example, the relay connector ( 106   c ) will be described in detail with reference to  FIGS.  35  and  36   . 
     For example, as shown in  FIG.  35   , the first plug holder  106   a  can be attached to the side face of the first linear motor, the first tab holder  106   b  can be attached to the side face of the second linear motor, and the first plug holder  106   a  and the first tab holder  106   b  can be aligned in the direction of connection of the linear motors. 
     For example, as shown in  FIG.  36   , a terminal and/or a contact and/or the like may be provided in each of the first plug holder  106   a  and the first tab holder  106   b , and the relay connector  106   c  having a terminal and/or a contact and/or the like having a shape adaptable to the shape of each terminal and/or contact and/or the like can be attached to both the first plug holder  106   a  and the first tab holder  106   b . The relay connector  106   c  can be attached to the first plug holder  106   a  and the first tab holder  106   b  from a direction (the Y direction) perpendicular to the series direction of the linear motors. The relay connector  106   c  can be attached to the first plug holder  106   a  and the first tab holder  106   b , for example, by engagement and/or mating. 
     It is preferred that the relay connector  106   c  be configured to be electrically and physically engageable and/or mateable with the first plug holder  106   a  and/or the first tab holder  106   b.    
     The relay connector  106   c  can be so formed as to have a flat outer surface, so that the outer surface of the relay connector  106   c  can be arranged more flush with the side faces of the linear motors. 
     Using the first connector including the first plug holder  106   a , the first tab holder  106   b , and the relay connector  106   c  facilitates and ensures connection of the linear motors (LM 1 , LM 2 ). 
     Alternatively, as shown in  FIG.  37   , a first plug holder  106   a ′ and/or a first tab holder  106 ′ may have a hole such as a threaded hole, and further the relay connector  106   c ′ may also have a hole such as a threaded hole. These holes can be used to fix the first plug holder  106   a ′ and the first tab holder  106   b ′ more firmly and reliably with fasteners such as screws via the relay connector  106   c ′. The relay connector  106   c ′ can also function as a cover. This can more reliably prevent water, dust, and the like from entering the first plug holder  106   a ′ and/or the first tab holder  106   b′.    
     Such a cover as described above can also be provided in a case where the first plug holder and the first tab holder are directly electrically connected. See  FIGS.  16 ,  17   (A)- 17 (D), and  38 - 41 . 
     The first connector  107  shown in  FIGS.  16  and  17   (A)- 17 (D), for example, includes the first plug holder  107   a , the first tab holder  107   b , and the cover  107   c . More details are as shown in  FIGS.  38  to  41   . 
     For example, as shown in  FIG.  38   , the first plug holder  107   a  and the first tab holder  107   b  can be coupled together by sliding in the series direction (the X direction) of the linear motors. 
     Alternatively, as shown in  FIG.  39   , the first plug holder  107   a  and the first tab holder  107   b  can be coupled together by sliding in a direction (the Y direction) perpendicular to the series direction of the linear motors. 
       FIG.  40    shows a coupled state of the first plug holder  107   a  and the first tab holder  107   b.    
     For example, as shown in  FIG.  41   , the first connector  107  (see  FIGS.  16 ,  17   (A)- 17 (D), and  41 ) may further include the cover  107   c , and the first plug holder  107   a , the first tab holder  107   b , and the cover  107   c  may be fixed with fasteners such as screws (see  FIG.  41   ). 
     Therefore, both the first plug holder  107   a  and the first tab holder  107   b  may have a hole such as a threaded hole. The cover  107   c  may also have a hole such as a threaded hole. 
     These holes can be used to fix the first plug holder  107   a  and the first tab holder  107   b  more firmly and reliably with fasteners such as screws via the cover  107   c . The cover  107   c  can more reliably prevent water, dust, and the like from entering the first plug holder  107   a  and/or the first tab holder  107   b.    
     &lt;Other Forms of First Connector&gt; 
     Other forms of the first connector are shown in  FIGS.  18 - 29   (D). The first connector (for example, the connectors  108  to  116 ) may be a connector for connecting at least two linear motors (LM 1 , LM 2 ) in a series direction. The first connector (for example, the connectors  108  to  116 ) may include two tab holders (for example, the tab holders  108   a  to  116   a , the tab holders  108   b  to  116   b ) and a relay connector ( 108   c  to  116   c ) for electrically connecting these two tab holders. 
     These two tab holders may face each other at least along a direction of connection or the series direction of the linear motors (LM 1 , LM 2 ). 
     The two tab holders may be positioned in a recessed portion provided in side faces (the XZ plane) of connecting portions of the two linear motors (LM 1 , LM 2 ). 
     The connectors shown in  FIGS.  18 - 29   (D) are characterized in that the first connector (for example, the connectors  108  to  116 ) uses two tab holders (for examples, the tab holders  108   a  to  116   a , the tab holders  108   b  to  116   b ) in combination. 
     As shown in  FIGS.  18     19 (C),  FIGS.  20 - 21   (C),  FIGS.  22  to  23   ,  FIGS.  26 - 27   (C), and  FIGS.  28 - 29   (D), two tab holders having identical shapes may be used. See  FIGS.  19 (A)- 19 (C)  and  42 ) 
     Alternatively, as shown in  FIGS.  24 - 25   (D), two tab holders having different shapes may be used. See  FIGS.  48 (A)- 48 (C) and  49 (A)- 49 (C) . 
     The two tab holders may face each other along the direction of connection or the series direction of the linear motors (LM 1 , LM 2 ), but do not have to be electrically connected together (see  FIG.  43   ). 
     In the first connectors (for example, the connectors  108  to  116 ) shown in  FIGS.  18 - 29   (D), a relay connector (for example, the relay connectors  108   c  to  116   c ) for electrically connecting these tab holders may be used. See  FIGS.  43  and  44   (A) and  44 (B). 
     The relay connector may have a relay mechanism inside for electrically connecting the two tab holders. See  FIGS.  50 (A) and  50 (B) , and  51 (A) and  51 (B). 
     The relay connectors  108   c  to  116   c  shown in  FIGS.  18 - 29   (D) will be described in detail below. 
     &lt;Relay Connector&gt; 
     For example, as shown in  FIG.  42   , the tab holder  108   a  can be attached to the side face of the first linear motor, and the tab holder  108   b  can be attached to the side face of the second linear motor. Both the tab holder  108   a  and the tab holder  108   b  can be aligned in the direction of connection of the linear motors. 
     For example, as shown in  FIG.  42   , a terminal or a contact may be provided in each of the tab holder  108   a  and the tab holder  108   b , and the relay connector  108   c  having a terminal (which may alternatively be referred to as a “relay contact” or simply as a “contact”) having a shape such as is adapted to the shape of each terminal or contact can be attached to the tab holder  108   a  and the tab holder  108   b  (see  FIG.  43   ). The relay connector  108   c  can be attached to the tab holder  108   a  and the tab holder  108   b  from a direction (the Y direction) perpendicular to the series direction of the linear motors. The relay connector  108   c  can be electrically and physically attached to both the tab holder  108   a  and the tab holder  108   b , for example, by engagement and/or mating. 
     The relay connector  108   c  may include the slide plate  108   d . See  FIGS.  18  to  29   (D) and  44 (A) and  44 (B). The shape of the slide plate  108   d  is not particularly limited. 
     It is preferred that the slide plate  108   d  be attached slidably to the surface of the body of the relay connector  108   c  (see  FIGS.  18  to  29   (D) and  44 (A) and  44 (B)). It is preferred that the slide plate  108   d  have a surface substantially flush with the surfaces of the linear motors. See  FIGS.  18  to  29   (D) and  44 (A) and  44 (B). 
     The slide plate  108   d  may have a lock mechanism. Hence, the slide plate  108   d  can also be referred to as a “lock plate”. 
     For example, as shown in  FIGS.  42 - 44   (B), the slide plate  108   d  may be first positioned above an electrical joining portion of the tab holder  108   a . See  FIG.  44 (A) . The slide plate  108   d  at this time, as viewed from above, can substantially entirely cover the electrical joining portion of the left tab holder  108   a , and may be configured to be capable of covering the boundary between the tab holder  108   a  and the tab holder  108   b , or at least a portion of the tab holder  108   b . See  FIG.  44 (A) . 
     The slide plate  108   d , in a state shown in  FIG.  44 (A)  (referred to below as an “unlocked state”), may be configured not to substantially contact the left tab holder  108   a.    
     The slide plate  108   d , in a state shown in  FIG.  44 (B)  (referred to below as a “locked state”), may be configured to substantially contact the left tab holder  108   a  and be engaged therewith or caught thereon. 
     The slide plate  108   d , if necessary, may be configured to contact the right tab holder  108   b  and be engaged therewith or caught thereon. 
     More specifically, as shown in  FIGS.  44 (A) and  44 (B) , the slide plate  108   d  includes two projecting portions (R 1 , R 2 ) extending in the Z-axis direction (see  FIG.  44 (A) ). In the form shown, the projecting portion R 1  extends upward, and the projecting portion R 2  extends downward. 
     In the “unlocked state” shown in  FIG.  44 (A) , the two projecting portions (R 1 , R 2 ) are not substantially in contact with the left tab holder  108   a.    
     In the “locked state” shown in  FIG.  44 (B) , the slide plate  108   d  is slidingly moved, and the two projecting portions (R 1 , R 2 ) are in contact with portions of the left tab holders  108   a  (more specifically, two projecting portions (R 3 , R 4 ) extending in the Z-axis direction of the tab holder  108   a ). In the form shown, the projecting portion R 3  extends downward, and the projecting portion R 4  extends upward. 
     The two projecting portions (R 1 , R 2 ), if necessary, may contact portions of the right tab holders  108   b  (more specifically, two projecting portions (R 5 , R 6 ) extending in the Z-axis direction of the tab holder  108   b ). In the form shown, the projecting portion R 5  extends downward, and the projecting portion R 6  extends upward. 
     The shapes of the projecting portions (R 1  to R 6 ) are not particularly limited. They may have a plate-like shape, as in the form shown, or may have another geometric shape. Positions at which the projecting portions (R 1  to R 6 ) are arranged are not particularly limited, either. 
     Since the slide plate ( 108   d ) has the lock mechanism, the relay connector ( 108   c ) can be significantly prevented from being disengaged from the tab holders ( 108   a ,  108   b ). 
     In the present disclosure, the relay connectors  109   c  to  116   c  shown in  FIGS.  20  to  29   (A)- 29 (D) can be configured similarly to the relay connector  108   c.    
     For example, in  FIGS.  50 (A) and  50 (B) , the relay connector and the slide plate that can be used in the sixteenth embodiment are shown. 
       FIG.  50 (A)  shows an “unlocked state” (lock OFF) by the slide plate  116   d.    
       FIG.  50 (B)  shows a “locked state” (lock ON) by the slide plate  116   d.    
     As shown in  FIGS.  50 (A) and  50 (B) , a protrusion and a recess that can be engaged or mated together and slide on each other may be provided to the body of the relay connector and a back face of the slide plate  116   d.    
     Next, an internal structure of a relay connector will be described with reference to  FIGS.  51 (A) and  51 (B) .  FIGS.  51 (A) and  501 (B)  shows an internal structure of the relay connector  116   c  that can be used in the sixteenth embodiment (however, only a “locked state” is shown). 
     In  FIG.  51 (A) , the two tab holders ( 116   a ,  116   b ) are arranged facing each other, and the relay connector  116   c  is positioned therebetween. A relay contact is arranged inside the relay connector  116   c , and terminals or contacts provided in the two tab holders ( 116   a ,  116   b ) and the relay contact are electrically connected. 
     In  FIG.  51 (B) , the tab holders ( 116   a ,  116   b ) are shown arranged facing each other on two linear motors (LM 1 , LM 2 ), respectively, with the relay connector  116   c  positioned between the tab holders ( 116   a ,  116   b ). In addition, the slide plate  116   d  is shown in a locking position. 
     In a case where two tab holders are used in the first connector, the two tab holders may have substantially identical shapes. See  FIGS.  18 - 23   (C),  FIGS.  26 - 29   (D),  FIGS.  42 - 44   (B), and  FIGS.  50 (A) and  50 (B) . 
     For example, as shown in  FIG.  42   , using tab holders ( 108   a ,  108   b ) having identical shapes (see  FIG.  19 (C) ) facilitates arrangement of the tab holders to the linear motors and connection of a plurality of linear motors. 
     In a case where two tab holders are used in the first connector, the two tab holders may have different shapes. See  FIGS.  24 - 25   (D) and  48 (A)- 49 (C). 
     By using tab holders having different shapes, various kinds of tab holders can be be arranged in linear motors, thus increasing variations of connection of linear motors. 
     The tab holders may have at least one through-hole (see  FIGS.  24 - 25   (D) and  48 (A)- 49 (C)). Through such a through-hole, the tab holder may be fixed to the linear motor, in particular to the board that may be arranged inside the linear motor with a fastener such as a screw. See  FIGS.  24 - 29   (D) and  50 (A) and  50 (B). 
     In  FIGS.  24  to  29   , depictions are made with the board visible for the convenience in description. In other words, depictions are made without an overmolded portion (it should be noted that the overmolded portion is indicated by long dashed double-short dashed lines). 
     For example, as shown in  FIG.  50   , the tab holders can be fixed to the boards of the linear motors with fasteners such as screws. By using such a through-hole, the tab holders can be fixed to the linear motors using a smaller space. 
     A “Second connector” will be described below. 
     &lt;Second Connector&gt; 
     A second connector (for example, the connectors  200  to  216 ) may be positioned in a recessed portion provided in an edge portion of a side face (the XZ plane) of either one of two linear motors (LM 1 , LM 2 ). 
     The second connector (for example, the connectors  200  to  216 ) can be used with the first connector (for example, the connectors  100  to  116 ) (see  FIGS.  4  to  29   ). 
     For example, the second connector (for example, the connectors  201  to  216 ) may include a housing (for example, the housing  201   a  to  216   a ) for receiving a plurality of electrical wires (for example, the electrical wires  120  to  124 ), and a second tab holder ( 201   b  to  216   b ). See  FIGS.  4 - 29   (D). An “electrical wire” in the present disclosure means a thin and long member having conductivity, and may have include a terminal at its tip portion (see  FIG.  30   ). 
       FIG.  30 (A)  shows, for example, four electrical wires  121   a  for a power supply. The electrical wires  121   a  may include a terminal Ta for connection. 
       FIG.  30 (B)  shows, for example, two electrical wires  121   b  for a sensor such as a temperature sensor. The electrical wires  121   b  may include a terminal Tb for connection. 
     In the present disclosure, the purpose, length, diameter, and number of electrical wires are not particularly limited. 
     For example, as illustrated in the eleventh embodiment of  FIGS.  45  to  47   , six electrical wires ( 121   a  (four in number),  121   b  (two in number)) can be inserted into the housing  211   a  (see  FIG.  45   ). By coupling the housing  211   a  having the electrical wires ( 121   a ,  121   b ) inserted or set therein to the second tab holder  211   b  (see  FIGS.  46  to  47   ), the electrical wires ( 121   a ,  121   b ) can be more easily electrically connected to the linear motor. 
     A “housing” in the present disclosure generally means a member that can be arranged at an end portion of a side face (the XZ plane) of a linear motor, and that can accommodate an electrical wire or the like (see  FIG.  3   ). 
     A “second tab holder” in the present disclosure means a tab holder that can be arranged at an end portion of a side face (the XZ plane) of a linear motor (see  FIG.  3   ). 
     The “second tab holder” may have an identical shape to the “first tab holder” and/or either one of the “two tab holders” (preferably the tab holder on the LM 2  side) included in the “first connector”, or may have a different shape therefrom. 
     The second connector, for example, the housing and the second tab holder, may be positioned substantially flush with the side face of the linear motor. See  FIGS.  4 - 29   (D). 
     By positioning the housing and the second tab holder substantially flush with the side face of the linear motor, the possibility is significantly reduced that they may prevent motion in the series direction or the direction of movement or the direction of connection of the linear motor. 
     In the second connector, at least a portion of the housing may be engaged with a portion of the second tab holder. More specifically, as shown in the first to third embodiments and in the eleventh to sixteenth embodiments, an engaging portion provided to the housing and an engaging portion provided to the second tab holder may be coupled together. 
     The housing  201   a  of the first embodiment, for example, may have an engaging portion that may be provided similarly to the engaging portion E 1  of the plug holder  101   a  shown in  FIG.  31 (A)- 31 (C) , the second tab holder  210   b  may also have an engaging portion that may be provided similarly to the engaging portion E 2  of the tab holder  101   b , and these engaging portions may be engaged and coupled together (see  FIG.  31 (B) ). 
     The housing  202   a  of the second embodiment may similarly have an engaging portion E 7 , which may be engaged and coupled with an engaging portion E 8  provided to the second tab holder  202   b . See  FIGS.  34 (A) and  34 (B) . 
     The housing  203   a  of the third embodiment may similarly have an engaging portion E 5 , which may be engaged and coupled with an engaging portion E 6  provided to the second tab holder  203   b . See  FIGS.  32 ,  33   (A) and  33 (B). 
     The housing  211   a  of the eleventh embodiment may similarly have an engaging portion E 9 , which may be engaged and coupled with an engaging portion E 10  provided at the second tab holder  211   b . See  FIGS.  47 (A) and  47 (B) . 
     An engaging portion can similarly be formed on the housing  212   a  to  216   a  of the twelfth to sixteenth embodiments. See  FIGS.  24 - 29   (D). 
     For example, an engaging portion that may be provided to the housing  216   a  can be configured not to protrude at all from the side face of the linear motor (see  FIG.  29 (A) ). Therefore, the surface of the housing  216   a  can be positioned more flush with the side face of the linear motor. 
     The positions of the engaging portions that can be provided to the housings are not particularly limited. The positions and/or shapes of the engaging portions that can be provided to the second tab holders are not particularly limited, either. 
     The second tab holder (for example, the tab holders  201   b  to  205   b ) may have a substantially identical shape to the first tab holder (for example, the tab holders  101   b  to  105   b ). See  FIGS.  4 - 13   (C). 
     Making the shape of the second tab holder and the shape of the first tab holder substantially identical enables a plurality of linear motors to be more quickly connected. 
     The second tab holder (for example, the tab holders  206   b  to  216   b ) may have a substantially identical shape to either one of the two tab holders (for example, the tab holders  106   b  to  116   b ). See  FIGS.  14 - 29   (D). 
     Making the shape of the second tab holder and the shape of either one of the two tab holders substantially identical enables a plurality of linear motors to be more quickly connected. 
     The second tab holder and the first plug holder may be electrically connected inside the linear motor. For example, the second tab holder and the first plug holder can be electrically connected through a trunk line or an electrical wire inside the linear motor. Alternatively, they may be electrically connected via a board. By such configurations, space savings inside the linear motor can be achieved. 
     The second tab holder and either one of the two tab holders (for example, a tab holder of the first linear motor) may be electrically connected inside the linear motor. For example, the second tab holder and either one of the two tab holders (preferably the tab holder on the LM 1  side) may be electrically connected via a board inside the linear motor. See  FIGS.  24 - 29   (D). By such a configuration, a further improvement in space efficiency inside the linear motor can be achieved. 
     A “third connector” will be described below. 
     &lt;Third Connector&gt; 
     A third connector (for example, the connectors  300  to  316 ) may be positioned in a recessed portion provided in an edge portion of a side face (the XZ plane) of either one of two linear motors (LM 1 , LM 2 ). 
     The third connector can be used with the first connector and/or the second connector. See  FIGS.  4 - 29   (D). 
     In  FIGS.  4 - 29   (D), only a plug holder ( 301   a  to  307   a ) (see  FIGS.  4 - 17   (D)) or a tab holder ( 308   a  to  316   a ) (see  FIGS.  18 - 29   (D)) of the third connector ( 301  to  316 ) is shown for convenience in description. 
     The third connector may be a connector that may be used for connection in a series direction to a third linear motor. Therefore, the plug holders ( 301   a  to  307   a ) (see  FIGS.  4 - 17   (D)) and the tab holders ( 308   a  to  316   a ) ( FIGS.  18 - 29   (D)) shown in  FIGS.  4 - 29   (D) can be used appropriately in combination with the “tab holder” and/or the “relay connector” and/or the like described above of the present disclosure, and enables, if necessary, further connection in the series direction to the third linear motor. 
     The third connector may include a plug holder (for example, the plug holder  301   a  to  307   a ) (see  FIGS.  4 - 17   (D)), and such a plug holder may have a substantially identical shape to the first plug holder (for example, the first plug holder  101   a  to  107   a ). See  FIGS.  4 - 17   (D)). Making their shapes substantially identical enables a plurality of linear motors to be more quickly connected. 
     The third connector may include a tab holder (for example, the tab holders  308   a  to  316   a ) (see  FIGS.  18 - 29   (D)), and such a tab holder may have a substantially identical shape to either one of the two tab holders that may be included in the first connector (for example, the tab holders  108   a  to  116   a ). See  FIGS.  18 - 29   (D). Making their shapes substantially identical enables a plurality of linear motors to be more quickly connected. 
     The third connector may include a tab holder (for example, the tab holders  308   a  to  316   a ) (see  FIGS.  18 - 29   (D)), and such a tab holder may have a substantially identical shape to the second tab holder. Making their shapes substantially identical enables a plurality of linear motors to be more quickly connected. 
     The plug holder (for example, the plug holders  301   a  to  307   a ) of the third connector may be electrically connected to either one of the two tab holders (for example, the tab holders  101   b  to  107   b ) of the first connector inside the second linear motor LM 2 . See  FIGS.  4 - 17   (D). For example, the plug holders  301   a  to  307   a  and the tab holders  101   b  to  107   b  may be electrically connected through a trunk line or an electrical wire inside the linear motor. Alternatively, they may be electrically connected by a board. By such configurations, space savings inside the linear motor can be achieved. 
     The tab holder (for example, the tab holders  308   a  to  316   a ) of the third connector may be electrically connected to either one of the two tab holders (for example, the tab holders  108   b  to  116   b ) of the first connector inside the second linear motor LM 2 . See  FIG.  18 - 29   (D). For example, the tab holders  308   a  to  316   a  and the tab holders  108   b  to  116   b  may be electrically connected via a board inside the linear motor. See  FIGS.  24 - 29   (D). By such a configuration, a further improvement in space efficiency inside the linear motor can be achieved. 
     The third connector, as described above, may be a connector that may be used for connection to the next linear motor. 
     In a case where the third connector includes a tab holder, the tab holder included in the third connector may be covered with a cap  400  (see  FIGS.  52  and  65   (A)- 65 (G)) or an insulating member  450  (see  FIG.  53   ). 
     The shape of the cap  400  is not particularly limited as long as it can cover the tab holder, in particular a portion thereof that may be used for electrical coupling (see  FIGS.  52  and  65   (A)- 65 (G)). Material that may constitute the cap  400  is not particularly limited, either, and the cap  400  may be composed of, for example, resin or the like. The cap  400  improves performance, for example, waterproofness, dustproofness, and the like. 
     The shape of the insulating material  450  is not particularly limited as long as it can cover the tab holder, in particular a portion thereof that may be used for electrical coupling (see  FIG.  53   ). Material that may constitute the insulating member  450  is not particularly limited, either, and the insulating material may be composed of, for example, an insulating tape or the like. The insulating member  450  improves performance, for example, waterproofness, dustproofness, and the like. 
     &lt;Overmold&gt; 
     In the present disclosure, an overmold may form a side face (the XZ plane) or the like of a linear motor. 
     For example, as shown in  FIG.  54 (A) , an overmold OM may be so formed as to cover upper portions of coupled portions of the tab holder and the board. 
     Material that constitutes the overmold OM is not particularly limited, and may be a resin material, for example, plastic or the like. 
     For example, as shown in  FIG.  54 (B) , a step or a recessed portion may be provided at a portion of the tab holder on which the overmold OM may be formed, thereby improving a retaining force to the tab holder. 
     A “fourth connector” will be described below. 
     &lt;Fourth Connector&gt; 
     A fourth connector including a housing for receiving a plurality of other electrical wires, and a tab holder may be used in addition to the first connector, the second connector, and/or the third connector. 
     For example, the second connector shown in  FIGS.  4 - 13   (C),  FIGS.  24 - 25   (D) uses thick electrical wires ( 121   a ,  122   a ) for a power supply and thin electrical wires ( 121   b ,  122   b ) for a sensor such as a temperature sensor. For example, for the thin electrical wires ( 121   b ,  122   b ) for the sensor, a separate connector may be provided as the fourth connector. See  FIGS.  55 - 58   (B). It should be noted that the purpose of the electrical wires provided is not particularly limited. 
     For example, as shown in  FIGS.  55 ,  56   (A) and  56 (B), a fourth connector  501  for connecting, for example, two electrical wires  125  for a sensor may be provided on the side opposite to the second connector  200  including, for example, four electrical wires  120  for a power source. The purpose of the electrical wires provided is not particularly limited. 
     The fourth connector  501  includes a housing  501   a  for receiving the electrical wires  125 , and a tab holder  501   b . See  FIGS.  56 (A) and  56 (B) . A terminal or a contact for connection to a linear motor LM (in particular, a board contained therein) may be arranged in the tab holder  501   b . The terminal or the contact provided in the tab holder  501   b  may be configured to be electrically connectable to a terminal provided to the electrical wire  125  when the housing  501   a  and the tab holder  501   b  are coupled. A terminal and/or a contact and/or the like may also be provided inside the housing  501   a.    
     For example, as shown in  FIGS.  57 ,  58   (A) and  58 (B), a fourth connector  502  for connecting, for example, two electrical wires  126  for a sensor, may be provided on the side opposite to the second connector including, for example, four electrical wires  120  for a power source. The purpose of the electrical wires provided is not particularly limited. 
     The fourth connector  502  includes a housing  502   a  for receiving the electrical wires  126 , and a tab holder  502   b . See  58 (A) and  58 (B). A terminal or a contact (not shown) for connection to a linear motor LM (in particular, a board contained therein) may be arranged in the tab holder  502   b . The terminal or the contact provided in the tab holder  502   b  may be configured to be electrically connectable to a terminal provided to the electrical wire  126  when the housing  502   a  and the tab holder  502   b  are coupled. A terminal and/or a contact and/or the like may also be provided inside the housing  502   a.    
     The purpose, length, diameter, and number of electrical wires are not particularly limited. The fourth connector can be configured similarly to the second connector. 
     The connector of the present disclosure has been described with reference to the first to sixteenth embodiments, but these embodiments are only for illustrative purposes, and the first connector, the second connector, the third connector, and/or the fourth connector, if necessary, may be used in combination appropriately. Similarly, each component of the first connector, the second connector, the third connector, and/or the fourth connector, if necessary, may be used in combination appropriately. 
     &lt;Preferred Embodiment&gt; A preferred embodiment of the connector of the present disclosure will be shown for illustrative purposes in  FIGS.  59 - 65   (G) (the sixteenth embodiment). 
     It should be noted that such an embodiment of the present invention as described above encompasses the following preferred aspects. 
     First Aspect: 
     A connector for connecting at least two linear motors in a series direction, the connector including a first plug holder and a first tab holder, the first plug holder and the first tab holder facing each other along a direction of connection of the linear motors, the first plug holder and the first tab holder being positioned in a recessed portion provided in side faces of connecting portions of the two linear motors. 
     Second Aspect: 
     The connector according to the first aspect, wherein the first plug holder and the first tab holder are positioned substantially flush with the side faces of the linear motors. 
     Third Aspect: 
     The connector according to the first or second aspect, wherein at least a portion of the first plug holder is inserted into a portion of the first tab holder. 
     Fourth Aspect: The connector according to any one of the first to third aspects, wherein an engaging portion provided to the first plug holder and an engaging portion provided to the first tab holder are coupled together. 
     Fifth Embodiment 
     The connector according to the first or second aspect, further including a relay connector for electrically connecting the first plug holder and the first tab holder. 
     Sixth Embodiment 
     The connector according to the first or second aspect, further including a cover, the cover, the first plug holder, and the first tab holder being fixed with a fastener. 
     Seventh Embodiment 
     A connector for connecting at least two linear motors in a series direction, the connector including two tab holders and a relay connector for electrically connecting the two tab holders, the two tab holders facing each other along a direction of connection of the linear motors, the two tab holders being positioned in a recessed portion provided in side faces of connecting portions of the two linear motors. 
     Eighth Aspect: 
     The connector according to the seventh aspect, wherein the relay connector includes a slide plate. 
     Ninth Aspect: 
     The connector according to the eighth aspect, wherein the slide plate has a lock mechanism. 
     Tenth Aspect: 
     The connector according to any one of the seventh to ninth aspects, wherein the two tab holders have identical shapes. 
     Twelfth Aspect: 
     The connector according to any one of the seventh to eleventh aspects, wherein the tab holders have at least one through-hole, and the tab holders are fixed to the linear motors with a fastener through the through-hole. 
     Thirteenth Aspect: 
     The connector according to any one of the first to twelfth aspects, wherein the connector is used with a second connector positioned in a recessed portion provided in an edge portion of the side face of either one of the two linear motors, and the second connector includes a housing for receiving a plurality of electrical wires, and a second tab holder. 
     Fourteenth Aspect: 
     The connector according to the thirteenth aspect, wherein the housing and the second tab holder are positioned substantially flush with the side face of the linear motor. 
     Fifteenth Aspect: 
     The connector according to the fourteenth aspect, wherein at least a portion of the housing is engaged with a portion of the second tab holder. 
     Sixteenth Aspect: 
     The connector according to any one of the thirteenth to fifteenth aspects, wherein an engaging portion provided to the housing and an engaging portion provided to the second tab holder are coupled together. 
     Seventeenth Aspect: 
     The connector according to any one of the thirteenth to sixteenth aspects depending from any one of the first to sixth aspects, wherein the second tab holder have an identical shape to the first tab holder. 
     Eighteenth Aspect: 
     The connector according to any one of the thirteenth to sixteenth aspects depending from any one of the seventh to twelfth aspects, wherein the second tab holder has an identical shape to either one of the two tab holders. 
     Nineteenth Aspect: 
     The connector according to any one of the thirteenth to sixteenth aspects depending from any one of the first to sixth aspects, wherein the second tab holder and the first plug holder are electrically connected inside the linear motor. 
     Twentieth Aspect: 
     The connector according to any one of the thirteenth to sixteenth aspects depending from any one of the seventh to twelfth aspects, wherein the second tab holder and either one of the two tab holders are electrically connected inside the linear motor. 
     Twenty-first Aspect: 
     The connector according to any one of the first to twentieth aspects, wherein the connector is used with a third connector positioned in a recessed portion provided in an edge portion of the side face of either one of the two linear motors. 
     Twenty-second Aspect: 
     The connector according to the twenty-first aspect depending from any one of the first to sixth aspects, wherein the third connector includes a plug holder, and the plug holder has an identical shape to the first plug holder. 
     Twenty-third Aspect: 
     The connector according to the twenty-first aspect depending from any one of the seventh to twelfth aspects, wherein the third connector includes a tab holder, and the tab holder has an identical shape to either one of the two tab holders. 
     Twenty-fourth Aspect: 
     The connector according to the twenty-first aspect depending from any one of the thirteenth to sixteenth aspects, wherein the third connector includes a tab holder, and the tab holder has an identical shape to the second tab holder. 
     Twenty-fifth Aspect: 
     The connector according to the twenty-first aspect, wherein the third connector includes a tab holder, and the tab holder is covered with a cap or an insulating member. 
     Twenty-sixth Aspect: 
     The connector according to any one of the first to twenty-fifth aspects, wherein the connector is used with a fourth connector including a housing for receiving a plurality of electrical wires, and a tab holder. 
     The connector of the present disclosure can connect two or more linear motors in a series direction. The connector of the present disclosure can be used in linear motors in a variety of fields ranging from heavy industrial applications to light industrial applications. The connector of the present disclosure can be used in industrial machines, for example, servo linear motors and the like (for example, semiconductor manufacturing equipment and the like). 
     It should be appreciated for those skilled in this art that the above embodiments are intended to be illustrative, and not restrictive. For example, many modifications may be made to the above embodiments by those skilled in this art, and various features described in different embodiments may be freely combined with each other without conflicting in configuration or principle. 
     Although several exemplary embodiments have been shown and described, it would be appreciated by those skilled in the art that various changes or modifications may be made in these embodiments without departing from the principles and spirit of the disclosure, the scope of which is defined in the claims and their equivalents. 
     As used herein, an element recited in the singular and preceded with the word “a” or “an” should be understood as not excluding plural of said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property.