Patent Publication Number: US-11038291-B2

Title: Insulating cover

Description:
TECHNICAL FIELD 
     Embodiments of the present invention relate to an insulating cover. 
     BACKGROUND ART 
     As an insulating component for securing insulation of a tubular portion of a crimp terminal, a crimp terminal provided with an insulating sheath or a tubular insulating cap is known. 
     However, types of crimp terminals provided with insulating sheaths are classified depending on sizes of screws used for the crimp terminal in addition to sizes of electrical wires. Therefore, there is a need to store a varied inventory in a case where a crimp terminal provided with an insulating sheath is used. Also, it is difficult to perform retrofit or replacement in many cases in either case using a crimp terminal provided with an insulating sheath or using an insulating cap. 
     PRIOR ART LITERATURE 
     Patent Literature 
     
         
         [Patent Literature 1] 
         Japanese Unexamined Patent Application, First Publication No. H10-223280 
       
    
     SUMMARY OF INVENTION 
     Issue to be Solved by Invention 
     The issue to be solved by the present invention is to provide an insulating cover which has a high versatility and which is capable of undergoing retrofit or replacement. 
     Means for Solving the Issue 
     An insulating cover according to an embodiment is for an electrical connection structure that includes an electrical wire, a crimp terminal, and a terminal base. The electrical wire includes a conductor and an insulator. The insulator covers the conductor. An end portion of the conductor projects to an outside of the insulator. The crimp terminal includes a tubular portion into which the end portion of the conductor is inserted and a plate portion provided integrally with the tubular portion. The terminal base includes an electrical connection portion to which the plate portion is connected and a cover configured to cover the plate portion on a side opposite to the electrical connection portion. The insulating cover includes a cover main body and a pair of supporters. The cover main body is open in at least one direction along a radial direction of the tubular portion. The cover main body is configured to be disposed outside the terminal base. The cover main portion is configured not to cover at least a region of the plate portion. The region is configured to face the electrical connection portion. The cover main body is configured to cover the tubular portion. The pair of supporters is configured to face the electrical wire on a side opposite to the cover main body. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view illustrating an example of an electrical connection structure for explaining a first embodiment in a partially exploded manner  FIG. 2  is a perspective view illustrating an example of an electrical wire unit for explaining the first embodiment. 
         FIG. 3  is a diagram illustrating an example of a crimp terminal for explaining the first embodiment. 
         FIG. 4  is a perspective view illustrating the electrical wire unit and an insulating cover according to the first embodiment. 
         FIG. 5  is a perspective view illustrating the insulating cover according to the first embodiment. 
         FIG. 6  is a perspective view illustrating the insulating cover according to the first embodiment. 
         FIG. 7  is a sectional view illustrating the electrical wire unit and the insulating cover according to the first embodiment. 
         FIG. 8  is a sectional view illustrating a method for attaching the insulating cover to the electrical wire unit according to the first embodiment. 
         FIG. 9  is a perspective view illustrating the electrical wire unit and the insulating cover according to the first embodiment. 
         FIG. 10  is a perspective view illustrating a terminal base, a plurality of electrical wire units, and a plurality of insulating covers according to the first embodiment. 
         FIG. 11  is a perspective view illustrating an insulating cover according to a second embodiment. 
         FIG. 12  is a perspective view illustrating an electrical wire unit and the insulating cover according to the second embodiment. 
         FIG. 13  is a perspective view illustrating an electrical wire unit and an insulating cover according to a third embodiment. 
         FIG. 14  is a front view illustrating the electrical wire unit and the insulating cover according to the third embodiment. 
         FIG. 15  is a perspective view illustrating a terminal base, a plurality of electrical wire units, and a plurality of insulating covers according to the third embodiment. 
         FIG. 16  is a side view illustrating an insulating cover according to a fourth embodiment. 
         FIG. 17  is a side view illustrating the insulating cover according to the fourth embodiment. 
         FIG. 18  is a perspective view illustrating an insulating cover according to a fifth embodiment. 
         FIG. 19  is a perspective view illustrating an electrical wire unit and an insulating cover according to a sixth embodiment. 
     
    
    
     MODE FOR CARRYING OUT INVENTION 
     Hereinafter, insulating covers according to embodiments will be described with reference to drawings. In addition, the same reference numerals will be provided to components with the same or similar functions in the following description. And, repeated description of these components may be omitted. 
     First Embodiment 
     Referring to  FIGS. 1 to 10 , an insulating cover  100  according to a first embodiment will be described. First, an example of an electrical connection structure  10  for which the insulating cover  100  is used will be described. The electrical connection structure  10  is common in second to sixth embodiments, which will be described later, for example. However, the insulating cover  100  in each embodiment can be widely applied to various electrical connection structures that are not limited to the examples described below. 
       FIG. 1  is a perspective view illustrating an example of the electrical connection structure  10  in a partially exploded manner. The electrical connection structure  10  includes, for example, a plurality of electrical wires  200 , a plurality of crimp terminals  300 , a terminal base  400 , and a plurality of fixing members  500 . In addition, the crimp terminal  300  and the electrical wire  200  that are connected to each other will be collectively referred to as an “electrical wire unit U” in this specification. 
     The electrical wire  200  includes a conductor (inner conductor)  210  and an insulator (insulating layer)  220 . The conductor  210  may be formed of one wire W or may be formed of a plurality of wires W which are bundled. The conductor  210  has a substantially circular section. The insulator  220  cover a circumferential surface of the conductor  210 . The conductor  210  includes an end portion  211  that projects to the outside of the insulator  220 . 
     The crimp terminal  300  is a so-called bare crimp terminal. The crimp terminal  300  includes a tubular portion (crimp portion)  310  and a plate portion (terminal portion)  320 . 
     The tubular portion  310  is formed in a tubular shape, and the end portion  211  of the conductor  210  of the electrical wire  200  is inserted into the tubular portion  310 . The “tubular portion” and “tubular shape” in this specification are not limited to a case in which the tubular portion  310  is formed in a tubular shape in advance, and a case in which a material formed in a flat shape, a U shape, or the like is formed into a tubular shape so as to wrap around the conductor  210  at the time of connection to the conductor  210  is also included. Also, “insertion” in the specification is not limited to a case in which the end portion  211  of the conductor  210  is inserted into the tubular portion  310  formed in a tubular shape in advance, and a case in which the end portion  211  of the conductor  210  is located inside the tubular portion  310  by a material formed in a flat shape, a U shape, or the like being formed into a tubular shape so as to wrap around the conductor  210  is also included. The tubular portion  310  is crimped to the end portion  211  of the conductor  210  by applying a physical pressure to the end portion  211  of the conductor  210  using, for example, a crimp tool, a crimp machine, or the like. In this manner, the tubular portion  310  and the end portion  211  of the conductor  210  are physically and electrically connected to each other. 
     The plate portion  320  is provided integrally with the tubular portion  310 . The plate portion  320  extends in a plate shape in an axial direction of the tubular portion  310  from an end of the tubular portion  310  in a radial direction of the tubular portion  310 . The plate portion  320  has a through-hole  320   a . The through-hole  320   a  passes through the plate portion  320  in a thickness direction of the plate portion  320 . A fixing member  500  such as a screw or a bolt is caused to pass through the through-hole  320   a . The fixing member  500  includes a head portion  510  and an axis portion  520 . The axis portion  520  is thinner than the head portion  510  and has a screw thread formed thereon. 
     The terminal base  400  includes, for example, a terminal base main body  410  and a terminal base cover  420 . The terminal base main body  410  includes an insulating base  411  and a plurality of electrical connection portions (terminal base terminal portions)  412  provided at the base  411 . The base  411  includes standing walls  411   a  between the plurality of electrical connection portions  412 . 
     Each electrical connection portion  412  includes a metal component  412   a  to which the plate portion  320  of the crimp terminal  300  is connected. The electrical connection portion  412  has screw holes  412   b  that face the through-holes  320   a  of the crimp terminals  300 . The screw hole  412   b  may be provided at the metal component  412   a , or in a case in which a receiver that is different from the metal component  412   a  is provided on the back side of the metal component  412   a , the screw hole  412   b  may be provided at the receiver. The fixing member  500  that is caused to pass through the through-hole  320   a  of the crimp terminal  300  is engaged with the screw hole  412   b  of the electrical connection portion  412 . In this manner, the plate portion  320  of the crimp terminal  300  and the electrical connection portion  412  are physically and electrically connected to each other. 
     The terminal base cover  420  is formed in a plate shape that covers the plurality of electrical connection portions  412 , for example. The terminal base cover  420  is formed from an insulating material such as a synthetic resin. The terminal base cover  420  covers the plate portions  320  of the crimp terminals  300  on the side opposite to the electrical connection portions  412 . In the electrical connection structure  10 , a part of the plate portion  320  of the crimp terminal  300  and the tubular portion  310  are located outside the terminal base  400 , for example. The part of the plate portion  320  of the crimp terminal  300  and the tubular portion  310  are not covered with the terminal base cover  420 . 
       FIG. 2  is a perspective view illustrating an example of the electrical wire unit U. In the example illustrated in  FIG. 2 , a gap g is present in the axial direction of the tubular portion  310  between the tubular portion  310  of the crimp terminal  300  and the insulator  220  of the electrical wire  200 . The end portion  211  of the conductor  210  of the electrical wire  200  includes an exposed portion  211   a  that is exposed to the gap g between the tubular portion  310  and the insulator  220 . The gap g may be formed by attaching the crimp terminal  300  to the conductor  210  of the electrical wire  200  with a gap g intentionally provided therebetween, may be formed as a result in the process of bending or mounting the electrical wire  200 , may be formed by applying an external force to the insulator  220  and thus causing the insulator  220  to deviate (retreat) with respect to the conductor  210  such that the gap g is generated therebetween, or may be formed by other methods. 
     The plate portion  320  of the crimp terminal  300  includes a first region R 1  that faces the terminal base  400  and a second region R 2  that projects to the outside of the terminal base  400 . 
       FIG. 3  is a diagram illustrating an example of the crimp terminal  300 . The crimp terminal  300  is a crimp terminal through which a relatively large current flows, for example, and has a shape as follows in order to secure a large contact area with respect to the electrical connection portion  412  of the terminal base  400 . That is, the plate portion  320  of the crimp terminal  300  includes a first end portion  320   e   1  and a second end  320   e   2  located on the side opposite to the first end portion  320   e   1 . The first end portion  320   e   1  is an end connected to the tubular portion  310 . The first end portion  320   e   1  includes a straight portion SP that linearly extends on both sides of the tubular portion  310  in the width direction of the crimp terminal  300 . However, the shape of the crimp terminal  300  is not limited to the aforementioned example. 
     Next, the insulating cover  100  according to the embodiment will be described. 
       FIG. 4  is a perspective view illustrating the electrical wire unit U and the insulating cover  100 . The insulating cover  100  is formed from an insulating material such as a synthetic resin. Although a material of the insulating cover  100  is polycarbonate in one example, the material is not limited thereto. The insulating cover  100  is disposed outside the terminal base  400  and does not cover a greater part of the plate portion  320  of the crimp terminal  300 . The insulating cover  100  covers the tubular portion  310  of the crimp terminal  300 . 
     Here, a +X direction, −X direction, +Y direction, −Y direction, +Z direction, and −Z direction will be defined for convenience of explanation. The +X direction is a direction in which the insulating cover  100  is attached to the electrical wire unit U and is, for example, a direction that is substantially perpendicular to the plate portion  320  of the crimp terminal  300 . The +X direction is a direction along the radial direction of the tubular portion  310  of the crimp terminal  300 . The −X direction is a direction opposite to the +X direction. In a case in which the +X direction and the −X direction are not distinguished from each other, the directions will simply be referred to as an “X direction”. The +Y direction and the −Y direction are directions that are different from (for example, substantially perpendicular to) the X direction. The +Y direction is a direction from a second cover portion  112  toward a third cover portion  113  of a cover main body  110 , which will be described later. The −Y direction is a direction opposite to the +Y direction. In a case in which the +Y direction and the −Y direction are not distinguished from each other, the directions will simply be referred to as a “Y direction”. The +Z direction and the −Z direction are directions that are different from (for example, substantially perpendicular to) the X direction and the Y direction and are directions along the axial direction of the tubular portion  310 . The +Z direction is a direction from the insulator  220  of the electrical wire  200  toward the tubular portion  310  of the crimp terminal  300 . The −Z direction is a direction opposite to the +Z direction. In a case in which the +Z direction and the −Z direction are not distinguished from each other, the directions will simply be referred to as a “Z direction”. In the embodiment, the +X direction is an example of a “first direction”. The +Z direction is an example of a “second direction”. The −Z direction is an example of a “third direction”. 
       FIG. 5  is a perspective view illustrating the insulator  100 . The insulator  100  includes, for example, the cover main body  110 , an engagement portion  120 , and a pair of supporters  130 A and  130 B. 
     First, the cover main body  110  will be described. The cover main body  110  is open in at least one direction (for example, the +X direction) along the radial direction of the tubular portion  310  of the crimp terminal  300 . The cover main body  110  is disposed outside the terminal base  400 , does not cover at least a region, which faces the electrical connection portion  412  of the terminal base  400 , of the plate portion  320  of the crimp terminal  300 , and covers the tubular portion  310  of the crimp terminal  300 . The cover main body  110  has, for example, a first cover portion  111 , the second cover portion  112 , the third cover portion  113 , and cut-off portions  114 A and  114 B. The cut-off portions  114 A and  114 B will be described later. 
     The first cover portion  111  is formed in a plate shape along the Y direction and the Z direction. The first cover portion  111  covers the tubular portion  310  of the crimp terminal  300  in the +X direction. The first cover portion  111  does not cover the first region R 1  of the plate portion  320  of the crimp terminal  300  and covers at least a part of the second region R 2  of the plate portion  320  in the +X direction. 
     The second cover portion  112  extends in the +X direction from the end of the first cover portion  111  on the −Y direction side. The second cover portion  112  is formed into a plate shape along the X direction and the Z direction. The second cover portion  112  covers the tubular portion  310  of the crimp terminal  300  in the +Y direction. In the embodiment, the second cover portion  112  extends further on the −Z direction side beyond the end of the first cover portion  111  on the −Z direction side. 
     The third cover portion  113  extends in the +X direction from the end of the first cover portion  111  on the +Y direction side. The third cover portion  113  is formed in a plate shape along the X direction and the Z direction. The third cover portion  113  covers the tubular portion  310  of the crimp terminal  300  in the −Y direction. That is, the cover main body  110  surrounds the tubular portion  310  of the crimp terminal  300  in three directions with the first to third cover portions  111 ,  112 , and  113 . The cover main body  110  has an open portion O that opens to the outside in the +X direction. The open portion O is formed between the end of the second cover portion  112  on the +X direction side and the end of the third cover portion  113  on the +X direction side. In the embodiment, the third cover portion  113  extends further on the side of the −Z direction beyond the end of the first cover portion  111  on the −Z direction side. 
     The insulating cover  100  may be provided with an identification display ID. The identification display ID may indicate a line number of the electrical wire  200  to which the insulating cover  100  is attached or may indicate a phase (a U phase, a V phase, or a W phase) of an AC power supplied to the electrical wire  200  to which the insulating cover  100  is attached. The identification display ID may be formed from irregularities provided on the surface of the insulating cover  100  or may be formed of display of a sticker or the like attached to the insulating cover  100 . Also, the identification display ID may include not only characters but also include only a single color or two or more colors. For example, the identification display ID may include different colors for the respective phases (a U phase, a V phase, and a W phase) of AD power. The identification display ID may be provided at two or more of the first cover portion  111 , the second cover portion  112 , and the third cover portion  113 . 
     Next, the engagement portion  120  will be described. The engagement portion  120  extends in the +X direction from the end of the first cover portion  111  on the −Z direction side. The engagement portion  120  is formed into a plate shape along the X direction and the Y direction. The engagement portion  120  includes an arc portion  121  along an outer shape (outer circumferential surface) of the conductor  210  of the electrical wire  200 . The arc portion  121  is engaged with a region, which is not covered with the tubular portion  310  of the crimp terminal  300 , at the end portion  211  of the conductor  210  in the +X direction. “Engagement” described in the specification widely means “in a relation”. That is, “engagement” not only means a case in which a secured state occurs between two members that are engaged with each other but also includes a case in which the two members are just in contact with each other. 
     In the embodiment, the engagement portion  120  is inserted between the gap g between the tubular portion  310  of the crimp terminal  300  and the insulator  220  of the electrical wire  200  and is engaged with the exposed portion  211   a  that is exposed to the gap g at the end portion  211  of the conductor  210  (see  FIG. 4 ). In the case in which the engagement portion  120  is inserted between the tubular portion  310  of the crimp terminal  300  and the insulator  220  of the electrical wire  200 , the engagement portion  120  faces the tubular portion  310  of the crimp terminal  300  in the +Z direction and faces the insulator  220  of the electrical wire  200  in the −Z direction. In this manner, the position of the engagement portion  120  in the +Z direction (the position of the insulating cover  100  in the +Z direction) is restricted by the tubular portion  310  of the crimp terminal  300 . Meanwhile, the position of the engagement portion  120  in the −Z direction (the position of the insulating cover  100  in the −Z direction) is restricted by the insulator  220  of the electrical wire  200 . For example, the engagement portion  120  is in contact with both the tubular portion  310  of the crimp terminal  300  and the insulator  220  of the electrical wire  200  and is pinched with the tubular portion  310  and the insulator  220 . The engagement portion  120  may be in contact with either the tubular portion  310  or the insulator  220  in a case in which the gap g is greater than the thickness of the engagement portion  210 , for example. 
       FIG. 6  is a perspective view of the insulating cover  100  when seen at another angle. In the embodiment, the arc portion  121  of the engagement portion  120  is formed at an angle that is greater than 180 degrees and defines a space S, into which the conductor  210  of the electrical wire  200  is inserted, inside the engagement portion  120 . The space S is open on the +X direction side. The space S has a central portion Sa located at the center of the space S and an inlet portion Sb located on the +X direction side with respect to the central portion Sa. The width W 2  of the inlet portion Sb in the Y direction is narrower than the width W 1  of the central portion Sa in the Y direction. In this manner, the engagement portion  120  is formed in a U hole shape with a narrow entrance. 
     In the embodiment, the width W 1  of the central portion Sa in the Y direction is substantially the same as the diameter of the conductor  210  of the electrical wire  200 . Meanwhile, the width W 2  of the inlet portion Sb in the Y direction is smaller than the diameter of the conductor  210  of the electrical wire  200 . The engagement portion  120  is elastically deformed such that the conductor  210  of the electrical wire  200  is able to pass therethrough in a case in which the conductor  210  of the electrical wire  200  is pressed against the engagement portion  120 . In this manner, the conductor  210  of the electrical wire  200  passes through the inlet portion Sb and is then inserted into the central portion Sa of the space S. The conductor  210  of the electrical wire  200  inserted into the central portion Sa of the space S is not easily pulled out of the space S sine the width of the inlet portion Sb is narrower than the diameter of the conductor  210 . In a case in which the conductor (inner conductor)  210  of the electrical wire  200  is a stranded wire, the conductor  210  can be elastically deformed in a direction in which the conductor  210  becomes thinner or thicker by the positions of a plurality of wires W consisting of the stranded wire deviating from one another. Therefore, in a case in which the conductor  210  of the electrical wire  200  is pressed against the engagement portion  120 , the positions of the plurality of wires W consisting of the stranded wire deviate from one another, and the conductor  210  thus becomes thinner than the inlet portion Sb. In this manner, the conductor  210  of the electrical wire  200  may pass through the inlet portion Sb and be inserted into the central portion Sa of the space S. In this case, the conductor  210  is returned into an original shape by the conductor  210  reaching the central portion Sa of the space S, and the conductor  210  is thus not easily pulled out of the space S. 
     The above point will be described from another viewpoint. The engagement portion  120  includes a first portion  122   a , a second portion  122   b , and a third portion  122   c . The first portion  122   a  faces the conductor  210  of the electrical wire  200  in the +X direction. The second portion  122   b  faces the conductor  210  of the electrical wire  200  at a position that is different greater than 90 degrees in a first circumferential direction θ 1  with respect to the first portion  122   a . The first circumferential direction θ 1  is a direction along the outer shape (outer circumferential surface) of the conductor  210 . Meanwhile, the third portion  122   c  faces the conductor  210  of the electrical wire  200  at a position that is different greater than 90 degrees in a second circumferential direction θ 2  with respect to the first portion  122   a . The second circumferential direction θ 2  is a direction along the outer shape (outer circumferential surface) of the conductor  210  and is a direction opposite to the first circumferential direction θ 1 . A gap between the second portion  122   b  and the third portion  122   c  defines the inlet portion Sb of the space S. 
     Each of the second portion  122   b  and the third portion  122   c  are a support portion that supports the conductor  210  of the electrical wire  200  inserted into the central portion Sa of the space S in a direction different from that of the first portion  122   a . “Support” in the specification is not limited to a case in which the member is constantly in contact with a target to support the target but includes a case in which a gap is present between the member and the target and the member is brought into contact with the target and supports the target (restricts the position, for example) in a case in which an external force acts and the target moves (is inclined, for example), for example. 
     In the embodiment, the engagement portion  120  is not connected to the second cover portion  112  and the third cover portion  113  of the cover main body  110 . Therefore, elastic deformation of the engagement portion  120  is not restricted by the second cover portion  112  and the third cover portion  113 . Therefore, the engagement portion  120  can be elastically deformed in a relatively free manner such that the conductor  210  of the electrical wire  200  can pass through the inlet portion Sb. 
     Next, the pair of supporters  130 A and  130 B (the first support portion  130 A and the second support portion  130 B) will be described. The first support portion  130 A is provided at the end of the second cover portion  112  on the +X direction side. The first support portion  130 A is formed by bending the end of the second cover portion  112  on the +X direction side toward the inside of the insulating cover  100 , for example. The first support portion  130 A faces the electrical wire  200  and the tubular portion  310  of the crimp terminal  300  on the side opposite to at least a part (for example, the first cover portion  111 ) of the cover main body  110 . 
     In the embodiment, the first support portion  130 A is provided over the entire length of the second cover portion  112  in the Z direction. The first support portion  130 A includes a first portion  130 Aa located on the +Z direction side beyond the engagement portion  120  and a second portion  130 Ab located on the −Z direction side beyond the engagement portion  120 . The first portion  130 As faces the tubular portion  310  of the crimp terminal  300  on the side opposite to the first cover portion  111 . The second portion  130 Ab faces the insulator  220  of the electrical wire  200  on the side opposite to the first cover portion  111 . In the embodiment, the outer diameter of the insulator  220  of the electrical wire  200  is greater than the outer diameter of the tubular portion  310  of the crimp terminal  300 . For this reason, the second portion  130 Ab is brought into contact with the insulator  220  of the electrical wire  200  and supports the electrical wire  200 . In a case in which the outer diameter of the tubular portion  310  of the crimp terminal  300  is substantially the same as or greater than the outer diameter of the insulator  220  of the electrical wire  200 , the first portion  130 Aa may be brought into contact with the tubular portion  310  of the crimp terminal  300  and support the tubular portion  310  of the crimp terminal  300 . The first support portion  130 A may have only either the first portion  130 Aa or the second portion  130 Ab. In other words, the first support portion  130 A may support at least one of the electrical wire  200  and the tubular portion  310  of the crimp terminal  300 . 
     The second support portion  130 B is provided at the end of the third cover portion  113  on the +X direction side. The second support portion  130 B is formed by bending the end of the third cover portion  113  on the +X direction side toward the inside of the insulating cover  100 , for example. The second support portion  130 B faces the electrical wire  200  and the tubular portion  310  of the crimp terminal  300  on the side opposite to at least a part (for example, the first cover portion  111 ) of the cover main body  110 . 
     In the embodiment, the second support portion  130 B is provided over the entire length of the third cover portion  113  in the Z direction. The second support portion  130 B includes a first portion  130 Ba located on the +Z direction side beyond the engagement portion  120  and a second portion  130 Bb located on the −Z direction side beyond the engagement portion  120 . The first portion  130 Ba faces the tubular portion  310  of the crimp terminal  300  on the side opposite to the first cover portion  111 . The second portion  130 Bb faces the insulator  220  of the electrical wire  200  on the side opposite to the first cover portion  111 . In the embodiment, the second portion  130 Bb is brought into contact with the insulator  220  of the electrical wire  200  and supports the electrical wire  200 . In a case in which the outer diameter of the tubular portion  310  of the crimp terminal  300  is substantially the same as or greater than the outer diameter of the insulator  220  of the electrical wire  200 , the first portion  130 Ba may be brought into contact with the tubular portion  310  of the crimp terminal  300  and support the tubular portion  310  of the crimp terminal  300 . The first support portion  130 B may have only either the first portion  130 Ba or the second portion  130 Bb. In other words, the second support portion  130 B may support at least one of the electrical wire  200  and the tubular portion  310  of the crimp terminal  300 . 
       FIG. 7  is a sectional view illustrating the electrical wire unit U and the insulating cover  100 . The first support portion  130 A is located on the side opposite to the engagement portion  120  with respect to a part of the electrical wire  200  and supports the insulator  220  of the electrical wire  200  on the side opposite to the engagement portion  120 . Similarly, the second support portion  130 B is located on the side opposite to the engagement portion  120  with respect to a part of the electrical wire  200  and supports the insulator  220  of the electrical wire  200  on the side opposite to the engagement portion  120 . In this manner, the position of the electrical wire  200  is restricted between the engagement portion  120  and the pair of supporters  130 A and  130 B. In this manner, the insulting cover  100  does not easily fall off from the electrical wire unit U. 
       FIG. 8  is a sectional view illustrating a method for attaching the insulating cover  100  to the electrical wire unit U. The insulating cover  100  can be elastically deformed such that the first support portion  130 A and the second support portion  130 B are separated from each other. For example, the first support portion  130 A and the second support portion  130 B can move in a direction in which the first support portion  130 A and the second support portion  130 B are separated from each other by elastically deforming the second cover portion  112  and the third cover portion  113  with respect to the first cover portion  111 . In this manner, it is possible to insert the electrical wire unit U into the inside of the insulating cover  100 . 
     Here, the second cover portion  112  and the third cover portion  113  are not connected to the engagement portion  120  in the embodiment. Therefore, elastic deformation of the second cover portion  112  and the third cover portion  113  is not restricted by the engagement portion  120 . Therefore, the second cover portion  112  and the third cover portion  113  can be elastically deformed in a relatively free manner such that the electrical wire unit U is caused to pass between the first support portion  130 A and the second support portion  130 B. 
     Next, the cut-off portions  114 A and  114 B of the cover main body  110  will be described.  FIG. 9  is a perspective view illustrating the electrical wire unit U and the insulating cover  100 . In the embodiment, the cover main body  110  includes a first end portion  110   e   1  and a second end  110   e   2 . The first end portion  110   e   1  is an end on the +Z direction side. The first end portion  110   e   1  is an end located on the side opposite to the engagement portion  120  with respect to the first cover portion  111  in the Z direction. The second end  110   e   2  is an end on the −Z direction side and is located on the side opposite to the first end portion  110   e   1 . 
     Here, the plate portion  320  of the crimp terminal  300  has a first main surface  321 , a second main surface  322 , an end surface  323 , and side surfaces  324 . The first main surface  321  and the second main surface  322  are surfaces along the Y direction and the Z direction. Each of the first main surface  321  and the second main surface  322  is a surface with the largest area among the surfaces of the plate portion  320 . The first main surface  321  is directed in the −X direction. The first main surface  321  faces the head portion  510  of the fixing member  500  that is caused to pass through the through-hole  320   a  of the plate portion  320 . The second main surface  322  is located on the side opposite to the first main surface  321  and is directed in the +X direction. The end surface  323  is a surface located at the end of the plate portion  320  on the −Z direction side and along the X direction and the Y direction. The end surface  323  connects the first main surface  321  to the second main surface  322 . The end surface  323  defines the aforementioned straight portion SP. The side surface  324  is a surface directed in the +Y direction or the −Y direction among circumferential surfaces of the plate portion  320 . The side surface  324  substantially perpendicularly intersects with the first main surface  321  and connects the first main surface  321  to the second main surface  322 . 
     In the embodiment, a part of the first end portion  110   e   1  of the cover main body  110  projects on the +X direction side beyond the first main surface  321  of the plate portion  320  and faces the end surface  323  (that is, the straight portion SP) of the plate portion  320  in the +Z direction. In this manner, the position of the first end portion  110   e   1  of the cover main body  110  in the +Z direction (the position of the insulating cover  100  in the +Z direction) is restricted by the plate portion  320  of the crimp terminal  300 . In the embodiment, the first end portion  110   e   1  of the cover main body  110  faces the straight portion SP of the plate portion  320  in the +Z direction. In this manner, the position of the first end portion  110   e   1  of the cover main body  110  is more stably restricted. 
     In the embodiment, the pair of cut-off portions  114 A and  114 B (the first cut-off portion  114 A and the second cut-off portion  114 B) are provided at the first end portion  110   e   1  of the cover main body  110 . The first cut-off portion  114 A is formed by cutting-off the end of the second cover portion  112  on the +X direction side and the first support portion  130 A. In other words, the first cut-off portion  114 A is provided over the second cover portion  112  and the first support portion  130 A. The first cut-off portion  114 A is engaged with the plate portion  320  (for example, the straight portion SP of the plate portion  320 ) in the +Z direction and the +X direction. In this manner, the position of the insulating cover  100  in the +X direction (for example, the position of the second cover portion  112  in the +X direction) in addition to the position of the insulating cover  100  in the +Z direction is restricted by the plate portion  320  of the crimp terminal  300 . “Engaged” in the specification is not limited to a case in which the member is constantly in contact with a target but also includes a case in which a gap from the target is present and also the member is brought into contact with the target and is engaged with the target when an external force acts and the target thus moves (for example, the position thereof deviates), for example. In a case in which at least a part of another member is located in a space defined by the cut-off portion (the space surrounded in at least two directions by the cut-off portion), for example, the member is “engaged” in this specification. 
     Meanwhile, the second cut-off portion  114 B is formed by cutting-off the end of the third cover portion  113  on the +X direction side and the second support portion  130 B. In other words, the second cut-off portion  114 B is provided over the third cover portion  113  and the second support portion  130 B. The second cut-off portion  114 B is engaged with the plate portion  320  (for example, the straight portion SP of the plate portion  320 ) in the +Z direction and the +X direction. In this manner, the position of the insulating cover  100  in the +X direction (for example, the position of the third cover portion  113  in the +X direction) in addition to the position of the insulating cover  100  in the +Z direction is restricted by the plate portion  320  of the crimp terminal  300 . In the embodiment, rotation of the insulating cover  100  in the circumferential direction (the first circumferential direction θ 1  and the second circumferential direction θ 2 ) of the electrical wire  200  is restricted by each of the first and second cut-off portion s  114 A and  114 B being engaged with the plate portion  320 . 
     Next, a method for attaching the insulating cover  100  will be described. First, the end portion  211  of the conductor  210  of the electrical wire  200  is inserted into the tubular portion  310  of the crimp terminal  300 . Then, the tubular portion  310  of the crimp terminal  300  is crimped at the end portion  211  of the conductor  210  of the electrical wire  200  using a crimp tool, a crimp machine, or the like. In this manner, the electrical wire unit U including the electrical wire  200  and the crimp terminal  300  is provided. 
     The insulating cover  100  is attached to the electrical wire unit U before the electrical wire unit U is attached to the terminal base  400 , for example. Specifically, the insulating cover  100  is caused to be elastically deformed such that the first support portion  130 A and the second support portion  130 B are separated from each other, and the insulating cover  100  is attached to the electrical wire unit U in the +X direction. At this time, the conductor  210  of the electrical wire  200  passes through the inlet portion Sb of the space S and is inserted into the central portion Sa of the space S by the conductor  210  of the electrical wire  200  being pressed against the engagement portion  120  and the engagement portion  120  being elastically deformed. In a case in which the conductor (inner conductor)  210  of the electrical wire  200  is a stranded wire, the conductor  210  of the electrical wire  200  may pass through the inlet portion Sb of the space S and be inserted into the central portion Sa of the space S by the conductor  210  being pressed against the engagement portion  120 , the positions of the plurality of wires W included in the stranded wire deviating from one another, the conductor  210  becoming thinner than the inlet portion Sb. In this manner, the electrical wire  200  is supported by the first support portion  130 A, the second support portion  130 B, and the engagement portion  120  in a plurality of directions, and the insulating cover  100  is thus not easily detached from the electrical wire unit U. 
     Also, the engagement portion  120  of the insulating cover  100  is inserted between the tubular portion  310  of the crimp terminal  300  and the insulator  220  of the electrical wire  200 , and the cut-off portions  114 A and  114 B of the cover main body  110  are engaged with the plate portion  320  of the crimp terminal  300  in the embodiment. In this manner, positional deviation or rotation of the insulating cover  100  in the +Z direction, the −Z direction, the first circumferential direction θ 1 , and the second circumferential direction θ 2  are restricted. 
     After the insulating cover  100  is attached to the electrical wire unit U, the electrical wire unit U is attached to the terminal base main body  410 . In addition, the terminal base cover  420  is attached to the terminal base main body  410 . In this manner, the plate portion  320  of the crimp terminal  300  is covered with the terminal base cover  420 , and insulating properties are enhanced. 
     In addition, the method for attaching the insulating cover  100  is not limited to the aforementioned example. For example, the electrical wire unit U may be attached to the terminal base main body  410  before the insulating cover  100  is attached. In this case, the insulating cover  100  is attached to the electrical wire unit U after the electrical wire unit U is attached to the terminal base main body  410 . 
     Next, effects of the insulating cover  100  will be described. The insulating cover  100  is disposed outside the terminal base  400  and covers the tubular portion  310  of the crimp terminal  300  that is not covered with the terminal base cover  420 . In this manner, insulating properties of the tubular portion  310  of the crimp terminal  300  are enhanced. 
       FIG. 10  is a perspective view illustrating the terminal base  400 , the plurality of electrical wire units U, and the plurality of insulating covers  100 . In the configuration illustrated in  FIG. 10 , the plurality of electrical wire units U are attached to the single terminal base  400 . In addition, the insulating cover  100  is attached to each of the electrical wire units U. With such a configuration, insulating properties among the tubular portions  310  of the plurality of crimp terminals  300  are secured, and short-circuiting is prevented even in a case in which a conductive foreign matter M (for example, a facet) is brought into contact with the tubular portions  310  of the plurality of crimp terminals  300 . 
     With such a configuration, it is possible to provide the insulating cover  100  which has a high versatility and which is capable of undergoing retrofit or replacement. Hereinafter, details thereof will be described. In the related art, crimp terminals provided with insulating sheaths are used, or tubular insulating caps are attached in order to insulate the tubular portions  310  of the crimp terminals  300 . 
     The crimp terminals provided with the insulating sheaths are divided into types depending on sizes of screws of the crimp terminals in addition to sizes of the electrical wires. Therefore, it is necessary to have a large number of inventories in a case in which the crimp terminals provided with the insulating sheaths are used. Also, it is difficult to perform retrofit or replacement of the crimp terminals provided with the insulating sheaths, and it is necessary to cut the electrical wire  200  for replacement. The “retrofit” described in the specification means that a component for insulation is attached after the crimp terminal  300  is attached to the electrical wire  200 . Also, it is difficult to reuse the crimp terminal provided with the insulating sheath once the crimp terminal is attached. Further, the sizes of the crimp terminals provided with the insulating sheaths are typically up to a predetermined size (for example, 5.5 mm 2 ), and it is difficult to apply the crimp terminals provided with the insulating sheaths to thick wires. 
     Also, since it is necessary to cause the electrical wire  200  to pass through a tubular insulating cap before the crimp terminal  300  is connected to the electrical wire  200 , it is difficult to perform retrofit and replacement, and it is typically necessary to cut the electrical wire  200  for replacement. Further, since the tubular insulating cap is adapted such that the electrical wire  200  is just caused to pass therethrough, the position of the tubular insulating cap is not fixed. Therefore, there is a probability that the position of the insulting cap may deviate at the time of transport or device maintenance. If the position of the insulating cap deviates, the tubular portion of the crimp terminal may be exposed, or a part of the insulating cap may enter between the terminal base and the crimp terminal, which may lead to connection failure. Therefore, it is necessary to take an additional countermeasure, such as fixing of a part of the insulating cap to the terminal base, in many cases in order for the positions of the insulating caps not to deviate when the insulating caps are used. 
     Meanwhile, the insulating cover  100  according to the embodiment includes the cover main body  110  and the pair of supporters  130 A and  130 B. The cover main body  110  is open in at least one direction along the radial direction of the tubular portion  310  of the crimp terminal  300 . The cover main body  110  is disposed outside the terminal base  400 , does not cover at least the region, which faces the electrical connection portion  412  of the terminal base  400 , in the plate portion of the crimp terminal  300 , and covers the crimp terminal  300 . The pair of supporters  130 A and  130 B face the electrical wire  200  on the side opposite to the cover main body  110 . 
     With such a configuration, the shape of the insulating cover  100  does not depend on the shape of the plate portion  320  of the crimp terminal  300 , the size of the fixing member  500 , the shape of the terminal base  400 , and the like. The shape of the insulating cover  100  is determined depending only on the size of the electrical wire  200 , for example. Therefore, it is possible to reduce the types of insulating cover  100  as compared with a case in which a crimp terminal provided with an insulating sheath or, for example, an insulating cap that covers the plate portion  320  of the crimp terminal  300  is used. In this manner, it is possible to enhance versatility of the insulating cover  100 . 
     In addition, since the crimp terminal  300  is open in at least one direction along the radial direction of the tubular portion  310  of the crimp terminal  300 , it is possible to attach the insulating cover  100  to the electrical wire unit U through retrofit even after the crimp terminal  300  is attached to the electrical wire  200  and to replace the insulating cover  100  that has already been attached to the electrical wire unit U with another insulating cover  100  according to the insulating cover  100  in the embodiment. If the insulating cover  100  can undergo retrofit, it is possible to address problems in relation to insulation by post-attaching the insulating cover  100  without cutting or rearranging the electrical wire  200  even in a case in which such a problem occurs after a device is mounted, for example. Also, since it is not necessary to cause the electrical wire  200  to pass through the insulating cover  100  in advance unlike a tubular insulating cap, satisfactory attachment operability is also achieved. Further, it is also possible to reuse the insulating cover  100  that is once detached. In this manner, it is possible to enhance operability at the time of mounting or maintenance of the device and to reduce required costs. 
     In addition, the insulating cover  100  according to the embodiment is configured not to cover at least the region, which faces the electrical connection portion  412  of the terminal base  400 , in the plate portion  320  of the crimp terminal  300 , and it is thus possible to reduce the size thereof to be a size that is one size larger than the tubular portion  310  of the crimp terminal  300 , for example, regardless of the shape and the size of the plate portion  320  of the crimp terminal  300 . The insulating cover  100  with the size reduced in this manner can be applied to a location in which a plurality of electrical wire units U are disposed at a high density, for example, and it is possible to state that such an insulating cover  100  has higher versatility. 
     In addition, the insulating cover  100  according to the embodiment has a relatively simple configuration and is easily prepared for a thick electric wire or the like. Therefore, it is possible to secure insulation of the tubular portion  310  of the crimp terminal  300  with the insulating cover  100  even if the electrical wire  200  has a size that is greater than a predetermined size. 
     Also, according to the embodiment, the pair of supporters  130 A and  130 B that face the electrical wire  200  on the side opposite to the cover main body  110  are provided. With such a configuration, it is possible to curb the insulating cover  100  from falling off from the electrical wire unit U. 
     In the embodiment, the plate portion  320  of the crimp terminal  300  has the first region R 1  that faces the terminal base  400  and the second region R 2  that projects to the outside of the terminal base  400 . The cover main body  110  covers at least a part of the second region R 2  of the plate portion  320  of the crimp terminal  300 . With such a configuration, it is also possible to enhance insulation regarding the second region R 2  of the plate portion  320  exposed to the outside of the terminal base  400 . 
     In the embodiment, the insulating cover  100  includes the engagement portion  120 . The engagement portion  120  includes the arc portion  121  along the outer shape of the conductor  210  of the electrical wire  200  and engaged with a region, which is not covered with the tubular portion  310  of the crimp terminal  300 , at the end portion  211  of the conductor  210  of the electrical wire  200  in the +X direction. That is, the engagement portion  120  for fixing the insulating cover  100  is provided using the region, which is not covered with the tubular portion  310  of the crimp terminal  300 , at the end portion  211  of the conductor  210  of the electrical wire  200  by paying attention to the configuration in which there is such an uncovered region. With such a configuration, it is possible to reduce the size of the engagement portion  120  as compared with a case in which an arc-shaped engagement portion along the outer shape of the insulator  220  of the electrical wire  200  is provide since the conductor  210  is thinner than the insulator  220  of the electrical wire  200 . That is, it is possible to further enhance reliability of fixing the insulating cover  100  to the electrical wire  200  and to realize size reduction of the insulating cover  100  by providing the arc-shaped engagement portion  120  that is engaged with the conductor  210  of the electrical wire  200 . 
     In the embodiment, the engagement portion  120  is inserted between the tubular portion  310  of the crimp terminal  300  and the insulator  220  of the electrical wire  200  in the axial direction of the tubular portion  310  of the crimp terminal  300 . The engagement portion  120  faces the tubular portion  310  of the crimp terminal  300  in the +Z direction and faces the insulator  220  of the electrical wire  200  in the −Z direction. With such a configuration, it is possible to reliably restrict the position of the engagement portion  120  in the Z direction with respect to the electrical wire  200 . In this manner, it is possible to reduce the probability that the position of the insulating cover  100  deviates at the time of transporting or maintenance of the device, to curb the tubular portion  310  of the crimp terminal  300  from being exposed, and to curb occurrence of contact failure. 
     In the embodiment, the arc portion  121  of the engagement portion  120  is formed to be greater than 180 degrees and defines the space S into which the conductor  210  of the electrical wire  200  is inserted inside the engagement portion  120 . The space S has the central portion Sa and the inlet portion Sb located on the +X direction side with respect to the central portion Sa. The inlet portion Sb is narrower than the central portion Sa. With such a configuration, the insulating cover  100  is further unlikely to fall off from the electrical wire  200  in a case in which the conductor  210  of the electrical wire  200  is inserted into the central portion Sa. Also, since the arc portion  121  of the engagement portion  120  is an arc portion along the outer shape of the conductor  210  of the electrical wire  200 , it is possible to realize size reduction of the insulating cover  100  as compared with the case in which the engagement portion along the outer shape of the insulator  220  of the electrical wire  200  is provided even if the arc portion  120  is formed to be greater than 180 degrees in the embodiment. 
     In the embodiment, the cover main body  110  includes the first cover portion  111  that covers the tubular portion  310  of the crimp terminal  300  in the +X direction and the first end portion  110   e   1  located on the side opposite to the engagement portion  120  with respect to the first cover portion  111 . The first end portion  110   e   1  faces the plate portion  320  of the crimp terminal  300  in the +Z direction. With such a configuration, the restriction of the position with respect to the electrical wire unit U is performed with the engagement portion  120  and the first end portion  110   e   1  of the insulating cover  100  at positions on both sides of the first cover portion  111  in the Z direction, respectively. In this manner, the position of the insulating cover  100  is more easily stabilized. 
     In the embodiment, the first end portion  110   e   1  of the cover main body  110  has the cut-off portion  114 A that is engaged with the plate portion  320  of the crimp terminal  300  at least in the +Z direction. With such a configuration, the position of the cover main body  110  is more reliably restricted by the plate portion  320  of the crimp terminal  300 . In this manner, the position of the insulating cover  100  is more stabilized. 
     In the embodiment, the cut-off portion  114 A is engaged with the plate portion  320  of the crimp terminal  300  in the +X direction in addition to the +Z direction. With Such a configuration, rotation of the insulating cover  100  in the circumferential direction of the electrical wire  200  is curbed. In this manner, it is possible to avoid a situation in which one or more insulating covers  100  rotate and open portions of two insulating covers  100  face each other in the configuration as illustrated in  FIG. 10 , for example. 
     Second Embodiment 
     Next, a second embodiment will be described. The second embodiment is different from the first embodiment in that the insulating cover  100  has a lid  140 . In addition, configurations other than those described below are similar to those in the first embodiment. 
       FIG. 11  is a perspective view illustrating the insulating cover  100  according to the second embodiment. In the embodiment, the first support portion  130 A includes a first narrowed portion  131 A that is bent in a direction in which the first support portion  130 A approaches the second support portion  130 B. For example, the first narrowed portion  131 A is provided over the entire length of the second cover portion  112  in the Z direction. The first narrowed portion  131 A includes a first portion  131 Aa that is folded in a direction in which the first narrowed portion  131 A approaches the second support portion  130 B from the end of the second cover portion  112  on the +X direction side and a second portion  131 Ab that is folded in a direction opposite to that of the first portion  131 Aa from the end of the first portion  131 Aa on the +X direction side. 
     The first portion  131 Aa is formed to follow the outer shape of the insulator  220  of the electrical wire  200  and the outer shape of the tubular portion  310  of the crimp terminal  300  and faces the insulator  220  of the electrical wire  200  and the tubular portion  310  of the crimp terminal  300 . For example, the first portion  131 Aa is located on the side opposite to the engagement portion  120  with respect to a part of the electrical wire  200  and supports the insulator  220  of the electrical wire  200  on the side opposite to the engagement portion  120 . In a case in which the outer diameter of the tubular portion  310  of the crimp terminal  300  is substantially the same as or greater than the outer diameter of the insulator  220  of the electrical wire  200 , the first portion  131 Aa may support the tubular portion  310  of the crimp terminal  300  in addition to the insulator  220  of the electrical wire  200  or instead of the insulator  220  of the electrical wire  200 . 
     Similarly, the second support portion  130 B includes a second narrowed portion  131 B that is bent in a direction in which the second portion  130 B approaches the first support portion  130 A. For example, the second narrowed portion  131 B is provided over the entire length of the third cover portion  113  in the Z direction. The second narrowed portion  131 B includes a first portion  131 Ba that is folded in a direction in which the second narrowed portion  131 B approaches the first support portion  130 A from the end of the third cover portion  113  on the +X direction side and a second portion  131 Bb that is folded in a direction opposite to that of the first portion  131 Ba from the end of the first portion  131 Ba on the +X direction side. 
     The first portion  131 Ba is formed to follow the outer shape of the insulator  220  of the electrical wire  200  and the outer shape of the tubular portion  310  of the crimp terminal  300  and faces the insulator  220  of the electrical wire  200  and the tubular portion  310  of the crimp terminal  300 . For example, the first portion  131 Ba is located on the side opposite to the engagement portion  120  with respect to a part of the electrical wire  200  and supports the insulator  220  of the electrical wire  200  on the side opposite to the engagement portion  120 . In a case in which the outer diameter of the tubular portion  310  of the crimp terminal  300  is substantially the same as or greater than the outer diameter of the insulator  220  of the electrical wire  200 , the first portion  131 Ba may support the tubular portion  310  of the crimp terminal  300  in addition to the insulator  220  of the electrical wire  200  or instead of the insulator  220  of the electrical wire  200 . 
       FIG. 12  is a perspective view illustrating the electrical wire unit U and the insulating cover  100  according to the second embodiment. In the embodiment, the insulating cover  100  includes the lid  140  that is detachably attached to the cover main body  110  and covers the electrical wire  200  on the side opposite to the cover main body  110 . The lid  140  is formed frorm an insulating material such as a synthetic resin (for example, the same material as that of the cover main body  110 ). 
     The lid  140  includes a first engagement portion  141 A that is engaged with the first narrowed portion  131 A from the outside and a second engagement portion  141 B that is engaged with the second narrowed portion  131 B from the outside. The lid  140  is detachably attached to the cover main body  110  by the first and second engagement portions  141 A and  141 B being engaged with the first and second narrowed portions  131 A and  131 B. 
     With such a configuration, it is possible to secure higher insulation of the tubular portion  310  of the crimp terminal  300 . For example, it is possible to secure high insulation for the tubular portion  310  of the crimp terminal  300  with the configuration according to the embodiment even in a case in which the terminal base  400  is placed in a posture other than flat placement in addition to a case in which the terminal base  400  is flatly placed. “The case in which the terminal base  400  is flatly placed” means that the terminal base  400  is placed with the first main surface  321  of the crimp terminal  300  facing upward. “The case in which the terminal base  400  is placed in a posture other than flat placement” means, for example, a case in which the terminal base  400  is attached to a poll or the like with the first main surface  321  of the crimp terminal  300  directed in the horizontal direction and the terminal base  400  on the back side is exposed to the outside. In this case, the tubular portion  310  of the crimp terminal  300  on the back side is not covered, and the tubular portion  310  of the crimp terminal  300  is exposed to the outside of the insulating cover  100  according to the first embodiment. Therefore, in a case in which the terminal base  400  is mounted in a posture other than the flat placement, there still remains a probability that a conductive foreign matter M or the like flying over cooling wind, or the like is brought into contact with tubular portions  310  across a plurality of crimp terminals  300  and the tubular potions  310  of the plurality of crimp terminals  300  are short-circuited. 
     Thus, the insulating cover  100  further includes the lid  140  that is detachably attached to the cover main body  110  and covers the electrical wire  200  on the side opposite to the cover main body  110 . In this manner, the tubular portion  310  of the crimp terminal  300  is not exposed to the outside even in a case in which the terminal base  400  is placed in a posture other than flat placement. Therefore, it is possible to secure higher insulation for the tubular portion  310  of the crimp terminal  300 . Also, it is possible to omit the lid  140  in a case in which the terminal base  400  is flatly placed according to the embodiment. In this manner, it is possible to reduce the number of processes for a placement operation in the case in which the terminal base  400  is flatly placed. 
     In the embodiment, the pair of supporters  130 A and  130 B includes a pair of narrowed portions  131 A and  131 B that are provided at an end of the cover main body  110  and are bent in a direction in which the narrowed portions  131 A and  131 B approach each other. The lid  140  is attached to the cover main body  110  by being engaged with the pair of narrowed portions  131 A and  131 B. With such a configuration, it is possible to attach the lid  140  to the cover main body  110  using the supporters  130 A and  130 B that support the electrical wire  200 . In this manner, it is possible to simplify the shape of the insulating cover  100  as compared with a case in which a special structure for supporting the lid  140  is provided. In this manner, it is possible to realize reduction of manufacturing costs and the like of the insulating cover  100 . 
     Third Embodiment 
     Next, a third embodiment will be described. The third embodiment is different from the first embodiment in that the insulating cover  100  can be attached to the electrical wire unit U in a plurality of directions. In addition, configurations other than those described below are similar to those in the first embodiment. 
       FIG. 13  is a perspective view illustrating the electrical wire unit U and the insulating cover  100 . In the embodiment, it is possible to attach the insulating cover  100  to the electrical wire unit U in an arbitrary direction selected from a first attachment direction, a second attachment direction, and a third attachment direction in a case in which it is assumed that the same attachment direction as that in the first embodiment is the “first attachment direction, a direction that is different from the first attachment direction by 90 degrees in the second circumferential direction θ 2  is the “second attachment direction”, and a direction that is different from the first attachment direction by 90 degrees in the first circumferential direction θ 1  is the “third attachment direction” in regard to the attachment direction of the insulating cover  100  with respect to the electrical wire unit U. Each of the second attachment direction and the third attachment direction is substantially parallel to the first main surface  321  of the plate portion  320  of the crimp terminal  300 .  FIG. 13  illustrates the insulating cover  100  attached in the second attachment direction as a representative. 
       FIG. 14  is a front view illustrating the electrical wire unit U and the insulating cover  100 .  FIG. 14  illustrates the insulating cover  100  attached in the second attachment direction. In the embodiment, a first distance L 1  and a second distance L 2  will be defined as follows. The first distance L 1  is a distance between a virtual surface VS obtained by extending the side surface  324  of the plate portion  320  and the inner surface of the tubular portion  310  and is the shortest distance in the direction along the first main surface  321 . The second distance L 2  is a shortest distance between the inner surface of the first cover portion  111  and an end surface of the engagement portion  120  (the inner circumferential surface of the arc portion  121 ) in contact with the end portion  211  of the conductor  210 . In addition, the second distance L 2  is longer than the first distance L 1 . With such a configuration, it is possible to avoid interference between the first cover portion  111  of the insulating cover  100  and the plate portion  320  of the crimp terminal  300 , and attachment of the insulating cover  100  in the second attachment direction is allowed. In addition, the electrical wire unit U has a linearly symmetrical configuration in the left-right direction in  FIG. 14 . Also, the insulating cover  100  has a linearly symmetric configuration in the upward-downward direction in  FIG. 14 . Therefore, attachment of the insulating cover  100  in the third attachment direction is also allowed. 
     In addition, a third distance L 3  and a fourth distance L 4  are defined as follows in the embodiment. The third distance L 3  is a distance between the second main surface  322  of the plate portion  320  and the inner surface of the tubular portion  310  and is the shortest distance in a direction that is substantially perpendicular to the first main surface  321 . The fourth distance L 4  is a shortest distance between the inner surface of the third cover portion  113  and the end surface of the engagement portion  120  (the inner circumferential surface of the arc portion  121 ) in contact with the end portion  211  of the conductor  210 . In addition, the fourth distance L 4  is longer than the third distance L 3 . With such a configuration, the third cover portion  113  faces the second main surface  322  of the plate portion  320  in a case in which the insulating cover  100  is attached to the electrical wire unit U in the second attachment direction. The third cover portion  113  faces the second region R 2 , which projects to the outside of the terminal base  400 , in the plate portion  320 . The third cover portion  113  is substantially parallel to the second main surface  322  of the plate portion  320 . If the third cover portion  113  faces the second main surface  322  of the plate portion  320 , rotation of the insulating cover  100  in the circumferential directions (the first circumferential direction θ 1  and the second circumferential direction θ 2 ) of the electrical wire  200  is restricted. 
     In addition, a fifth distance L 5  is defined as follows in the embodiment. The fifth distance L 5  is a shortest distance between the inner surface of the second cover portion  112  and the end surface of the engagement portion  120  (the inner circumferential surface of the arc portion  121 ) in contact with the end portion  211  of the conductor  210 . In addition, the fifth distance L 5  is longer than the third distance L 3 . With such a configuration, the second cover portion  112  faces the second main surface  322  of the plate portion  320  in a case in which the insulating cover  100  is attached to the electrical wire unit U in the third attachment direction. The second cover portion  112  faces the second region R 2 , which projects to the outside of the terminal base  400 , in the plate portion  320 . The second cover portion  112  is substantially parallel to the second main surface  322  of the plate portion  320 . If the second cover portion  112  faces the second main surface  322  of the plate portion  320 , rotation of the insulating cover  100  in the circumferential directions (the first circumferential direction θ 1  and the second circumferential direction θ 2 ) of the electrical wire  200  is restricted. 
     Next, a method for using the insulating cover  100  according to the embodiment will be described.  FIG. 15  is a perspective view illustrating the terminal base  400 , a plurality of electrical wire units U, and a plurality of insulating covers  100 . As illustrated in  FIG. 15 , the plurality of insulating covers  100  are attached to the plurality of electrical wire units U in the mutually same direction. That is, an open portion O of an insulating cover O of the insulating cover  100  attached to an electrical wire unit U faces the first cover portion  111  of the insulating cover  100  attached to the next electrical wire unit U. 
     With such a configuration, the insulating cover  100  that enables selection of the first posture that is similar to that in the first embodiment, the second posture rotated by 90 degrees from the first posture, and the third posture rotated with respect to the first posture by 90 degrees in the direction opposite to that of the second posture as an attachment posture to the crimp terminal  300  is provided. In this manner, it is possible to attach the crimp terminal  300  in the posture in which the crimp terminal  300  is rotated by 90 degrees with respect to the terminal base  400 . In this manner, it is possible to avoid a situation in which open portions O of the plurality of insulating covers  100  are directed in the mutually same direction. In this manner, it is possible to prevent a situation in which a conductive foreign matter M is brought into contact with the tubular portions  310  of the plurality of crimp terminals  300  and the tubular portions  310  of the plurality of crimp terminals  300  are short-circuited even in a case in which the terminal base  400  are placed in a posture other than the flat placement similarly to the second embodiment. 
     Fourth Embodiment 
     Next, a fourth embodiment will be described. The fourth embodiment is different from the first embodiment in that the engagement portion  120  of the insulating cover  100  is provided so as to be inclined with respect to the first cover portion  111 . In addition, configurations other than those described below are similar to those in the first embodiment. 
       FIG. 16  is a side view illustrating the insulating cover  100  according to the fourth embodiment. In the embodiment, the engagement portion  120  is inclined so as to advance in the +Z direction with respect to the first cover portion  111  as the engagement portion  120  is separated from the first cover portion  111 . The engagement portion  120  is elastically deformable in the Z direction. 
       FIG. 17  is a side view illustrating a force acting on the insulating cover  100  attached to the electrical wire unit U. In the embodiment, a pressing force F of pressing a part of the insulating cover  100  (for example, the cut-off portions  114 A and  114 B) toward the plate portion  320  of the crimp terminal  300  acts on the insulating cover  100  in a case in which the engagement portion  120  is inserted between the tubular portion  310  of the crimp terminal  300  and the insulator  220  of the electrical wire  200  since the engagement portion  120  is inclined so as to advance in the +Z direction with respect to the first cover portion  111  as the engagement portion  120  is separated from the first cover portion  111 . For example, the part of the insulating cover  100  (for example, the cut-off portions  114 A and  1114 B) are pressed in the +X direction against the plate portion  320  of the crimp terminal  300  with the pressing force F. 
     With the configuration as described above, it is possible to curb backlash of the insulating cover  100 . That is, there may be a case in which the gap g between the tubular portion  310  of the crimp terminal  300  and the insulator  220  of the electrical wire  200  increases in a case in which a large number of bent portions are provided at the electrical wire  200  in the process of arranging the electrical wire  200  or for other reasons. It is conceivable that the insulating cover  100  causes backlash with respect to the electrical wire unit U if the gap g increases. 
     Thus, the engagement portion  120  is provided so as to be inclined with respect to the first cover portion  111  and can be elastically deformed in the axial direction of the tubular portion  310  with respect to the first cover portion  111  in the embodiment. With such a configuration, it is possible to allow the engagement portion  120  to have a width in the Z direction with the end of the engagement portion  120  on the +X direction side and the end of the engagement portion  120  on the −X direction side and thereby to address widening of the gap g to some extent. Even in a case in which the gap g between the tubular portion  310  of the crimp terminal  300  and the insulator  220  of the electrical wire  200  is large, for example, the engagement portion  120  can maintain contact with both the tubular portion  310  of the crimp terminal  300  and the insulator  220  of the electrical wire  200 . In this manner, it is possible to prevent backlash of the insulating cover  100  with respect to the electrical wire unit U. In addition, the engagement portion  120  is not limited to the case in which the engagement portion  120  is inclined so as to advance in the +Z direction with respect to the first cover portion  111  as the engagement portion  120  is separated from the first cover portion  111  and may be inclined so as to advance in the −Z direction with respect to the first cover portion  111  as the engagement portion  120  is separated from the first cover portion  111 . 
     In the embodiment, the engagement portion  120  is inclined so as to advance in the +Z direction with respect to the first cover portion  111  as the engagement portion  120  is separated from the first cover portion  111 . With such a configuration, the pressing force F of pressing a part of the insulating cover  100  (for example, the cut-off portions  114 A and  114 B) toward the plate portion  320  of the crimp terminal  300  acts on the insulating cover  100  by the engagement portion  120  being inserted between the tubular portion  310  of the crimp terminal  300  and the insulator  220  of the electrical wire  200 . With such a configuration, the position of the insulating cover  100  is further stabilized, and rotation of the insulating cover  100  is further reliably curbed. In addition, it is also possible to more reliably prevent backlash of the insulating cover  100  with respect to the electrical wire unit U. 
     Fifth Embodiment 
     Next, a fifth embodiment will be described. The fifth embodiment is different from the first embodiment in that the engagement portion  120  includes a projection  115 . In addition, configurations other than the configurations described below are similar to those in the first embodiment. 
       FIG. 18  is a perspective view illustrating the insulating cover  100  according to the fifth embodiment. In the embodiment, the insulating cover  100  includes a projection  115 . The projection  115  is provided at the first portion  122   a  of the engagement portion  120  and projects in the +X direction from the inner circumferential surface of the arc portion  121 . In the embodiment, the conductor  210  of the electrical wire  200  is formed of a plurality of wires W (see  FIG. 1 ). The projection  115  of the insulating cover  100  is inserted into the plurality of wires W in a case in which the engagement portion  120  is engaged with the conductor  210  of the electrical wire  200 . 
     With such a configuration, it is possible to restrict rotation of the insulating cover  100  in the circumferential directions (the first circumferential direction θ 1  and the second circumferential direction θ 2 ) of the electrical wire  200  by the projection  115  of the insulating cover  100  being inserted between the plurality of wires W. In addition, the insulating cover  100  includes two projections  115  in the embodiment. However, the number of projections  115  provided at the insulating cover  100  may be one, three, or more. 
     Sixth Embodiment 
     Next, a sixth embodiment will be described. The sixth embodiment is different from the first embodiment in that the engagement portion  120  is engaged with a tip end  211   b  of the electrical wire  200 . In addition, configurations other than the configurations described below are similar to those in the second embodiment. 
       FIG. 19  is a perspective view illustrating the electrical wire unit U and the insulating cover  100  according to the sixth embodiment. The end portion  211  of the conductor  210  of the electrical wire  200  has the tip end  211   b  that projects in the +Z direction from the tubular portion  310  of the crimp terminal  300 . 
     In the embodiment, the engagement portion  120  extends in the +X direction from the end of the first cover portion  111  on the +Z direction side. The engagement portion  120  is engaged with the tip end  211   b , which projects from the tubular portion  310 , of the end portion  211  of the conductor  210 . The engagement portion  120  faces the tubular portion  310  of the crimp terminal  300  in the −Z direction by being engaged with the tip end  211   b  of the end portion  211  of the conductor  210 . In this manner, the position of the engagement portion  120  in the −Z direction (the position of the insulating cover  100  in the −Z direction) is restricted by the tubular portion  310  of the crimp terminal  300 . 
     In the embodiment, the first and second supporters  130 A and  130 B are located on the +X direction side beyond a part of the plate portion  320  of the crimp terminal  300 . The first and second supporters  130 A and  130 B face the plate portion  320  of the crimp terminal  300  in the +Z direction. In this manner, the position of the insulating cover  100  in the +Z direction is restricted by the plate portion  320  of the crimp terminal  300 . 
     In the embodiment, each of the second portion  122   b  and the third portion  122   c  of the engagement portion  120  faces the first main surface  321  of the plate portion  320  of the crimp terminal  300  in the +X direction. In this manner, the second portion  122   b  and the third portion  122   c  of the engagement portion  120  restrict rotation of the insulating cover  100  in the circumferential directions (the first circumferential direction θ 1  and the second circumferential direction θ 2 ) of the electrical wire  200 . 
     With such a configuration, it is possible to provide highly versatile insulating cover  100  that can undergo retrofit or replacement for the purposes similar to those in the first embodiment. 
     Although the first to sixth embodiments have been described above, embodiments are not limited to the above examples. For example, the example in which the cover main body  110  is open only in one direction has been described in the aforementioned embodiments. However, the cover main body  110  may be open in a plurality of directions. The plate portion  320  of the crimp terminal  300  may not have the straight portion SP. 
     According to at least one of the aforementioned embodiments, the insulating cover includes the cover main body and the pair of supporters. The cover main body is open in one direction along the radial direction of the tubular portion of the crimp terminal, is disposed outside the terminal base, does not cover at least the region, which faces the electrical connection portion of the terminal base, in the plate portion of the crimp terminal, and covers the tubular portion. The pair of supporters face at least one of the electrical wire and the tubular portion on the side opposite to the cover main body. With such a configuration, it is possible to provide a highly versatile insulating cover that can undergo retrofit or replacement. 
     Although some embodiments of the invention have been described above, these embodiments are presented just as examples and are not intended to limit the scope of the invention. These embodiments can be performed in other various modes, and various omissions, replacement, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the invention described in the claims and the scope equivalent thereto as in the scope and the gist of the invention. 
     REFERENCE SIGNS LIST 
     
         
         
           
               10  Electrical connection structure 
               100  Insulating cover 
               110  Cover main body 
               111  First cover portion 
               112  Second cover portion 
               113  Third cover portion 
               114 A,  114 B Cut-off portion 
               115  Projection 
               120  Engagement portion 
               121  Arc portion 
               130 A,  130 B Supporter 
               131 A,  131 B Narrowed portion 
               140  Lid 
               200  Electrical wire 
               210  Conductor 
               211  End portion 
               220  Insulator 
               300  Crimp terminal 
               310  Tubular portion 
               320  Plate portion 
               320   a  Through-hole 
               321  First main surface 
               322  Second main surface 
               324  Side surface 
               400  Terminal base 
               412  Electrical connection portion 
               420  Terminal base cover 
               500  Fixing member 
               510  Head portion 
             R 1  First region of plate portion 
             R 2  Second region of plate portion 
             S Space 
             Sa Central portion 
             Sb Inlet portion