Attachment plug

Abstract

To prevent defects such as short circuits from occurring between a connecting portion between a plug blade and an electric wire and a connecting portion between a terminal piece of a thermostat and an electric wire.SOLUTION: An attachment plug includes a thermostat 13 that detects an overheating state and cuts off the current, a plug body 15 that incorporates the thermostat 13, a pair of blades 12 that protrude outward from the plug body 15 and are arranged in parallel on the left and right and spaced apart from each other when viewed from the front, and a pair of electric wires 14 that are introduced into the plug body 15 from the outside of the plug body 15 and connected to the corresponding blades 12, and the thermostat 13 includes a thermo body 131 and a pair of terminal pieces 132 to which the electric wires 14 are connected and that protrude in opposite directions from the thermo body 131 when viewed from the front, and the pair of terminal pieces 132a, 132b are arranged evenly on the left and right and parallel to the arrangement direction of the pair of blades 12 that are lined up on the left and right.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an attachment plug having a built-in thermostat as a temperature sensor that detects an abnormal temperature such as an overheated state and cuts off current. [Background technology]

[0002] The applicant proposed an invention in Patent Document 1 below relating to an attachment plug that can prevent tracking ignition at low cost without using a thermistor.

[0003] The attachment plug of Patent Document 1 has a built-in thermostat that is connected to an electric wire and has a pair of terminal pieces that protrude from the thermostat main body, and one of the pair of terminal pieces is positioned to protrude so as to be inserted into the gap between a pair of plug blades (see Figure 4 of Patent Document 1).

[0004] However, as shown in Patent Document 1, when the terminal piece is inserted into the gap between a pair of blades, the connection between the blade and the electric wire and the connection between the terminal piece and the electric wire are positioned close to each other. In other words, the distance between the opposite poles becomes extremely narrow, which raises concerns about problems such as the two connection parts accidentally coming into contact with each other, causing a short circuit or causing the thermostat to malfunction. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-164461 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in consideration of such problems, and aims to provide an attachment plug that can improve reliability by preventing defects such as short circuits between the connection portion between the plug blade and the electric wire and the connection portion between the terminal piece and the electric wire. [Means for solving the problem]

[0007] The attachment plug of this invention comprises a thermostat that detects an overheating state and cuts off the current, a plug body that incorporates the thermostat, a pair of blades that protrude outward from the plug body and are arranged in parallel on the left and right and spaced apart from each other when viewed from the front, and a pair of electric wires that are introduced into the plug body from a direction perpendicular to the protruding direction of the blades on the outside of the plug body and connected to the corresponding blades, and the thermostat comprises a thermo main body and a pair of terminal pieces to which the electric wires are connected and that protrude in opposite directions from the thermo main body when viewed from the front, and the pair of terminal pieces are arranged evenly on the left and right and parallel to the arrangement direction of the pair of blades that are lined up on the left and right.

[0008] In this configuration, the distance between the connecting portion between the blade and the electric wire and the connecting portion between the terminal piece and the electric wire can be made longer than in a configuration in which the terminal piece is disposed between a pair of blades. [Effects of the Invention]

[0009] According to the above configuration, it is possible to prevent malfunctions such as a short circuit caused by the connection portion between the plug blade and the electric wire and the connection portion between the terminal piece and the electric wire coming into unintended contact with each other, or the thermostat not operating properly, thereby improving the reliability of the attachment plug. [Brief explanation of the drawings]

[0010] [Figure 1] A perspective view of the attachment plug as seen from the blade side [Figure 2] Cross section of Figure 1 taken along the arrow AA [Figure 3] Cross-sectional view of arrow BB in Figure 2, partially seen from the left side [Figure 4] Rear view of the blade holding member [Figure 5] FIG. 10 is a rear view of the blade holder with the electric wire, thermostat, and blades mounted thereon. [Figure 6] (a) is a cross-sectional view of the main part as seen from the arrow HH in FIG. 5, and (b) is a cross-sectional view of the main part as seen from the arrow II in FIG. 5. [Figure 7] Cross section of Figure 4 taken along the CC arrow [Figure 8] Cross section of Fig. 4 taken along the arrow DD [Figure 9] Cross section of Fig. 4 taken along the arrows EE [Figure 10] FF arrow cross section of Figure 4 [Figure 11] Cross section of Figure 4 (GG arrows) DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, arrow F indicates the front (front side) of the attachment plug, and similarly, arrow U indicates upward, arrow R indicates right, and arrow L indicates left.

[0012] An embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a perspective view of the attachment plug 11 as seen from the front left side, Fig. 2 is a cross-sectional view taken along the line AA in Fig. 1 (in other words, a cross-sectional view taken along the line AA in Fig. 3), and Fig. 3 is a cross-sectional view taken along the line BB in Fig. 2. However, Fig. 3 shows the pair of electric wires 14 (14a, 14b), the pair of blades 12 (12a, 12b), and the thermostat 13 as seen from the left side of the attachment plug 11 (the direction of the arrow DR in Fig. 2).

[0013] As shown in these figures, the attachment plug 11 has two blades 12 (12a, 12b), as well as a thermostat 13 that detects an overheating condition and cuts off the current, a cord 4, and a plug body 15 that houses these.

[0014] The plug body 15 is composed of a blade holder 21 that holds the blades 12 and a plug body 28 that covers the blade holder 21.

[0015] In this embodiment, the blade holder 21 is made of a thermosetting resin such as melamine, and the plug body 28 is made of a thermoplastic resin such as polyvinyl chloride.

[0016] The blades 12 and thermostat 13 are housed together with the distal end portion 4T of the cord 4 in an internal space 21s of the blade holder 21 (see FIGS. 2 and 3 ), and are held in this state by being covered by the plug body 28. That is, the blade holder 21, blades 12, thermostat 13, and cord 4 are held with their respective predetermined portions embedded in the plug body 28.

[0017] The plug body 15 has a flat contact surface 15A on the front surface thereof that contacts an outlet or a power strip (not shown) that is an insertion receiving portion when the blade 12 is inserted. The contact surface 15A has an exposed surface 21A at the center thereof in a front view, which exposes a part of the blade holding member 21. The exposed surface 21A is flush with the outer periphery 15a of the contact surface 15A.

[0018] 4 is a rear view of the blade holder 21, FIG. 5 is a rear view of the blade holder 21 with the electric wire 14, the thermostat 13 and the blade 12 mounted thereon, FIG. 6(a) is a cross-sectional view of the main part taken along the arrow HH in FIG. 5, FIG. 6(b) is a cross-sectional view of the main part taken along the arrow II in FIG. 5, FIG. 7 is a cross-sectional view taken along the arrow CC in FIG. 4, FIG. 8 is a cross-sectional view taken along the arrow DD in FIG. 4, FIG. 9 is a cross-sectional view taken along the arrow EE in FIG. 4, FIG. 10 is a cross-sectional view taken along the arrow FF in FIG. 4, and FIG. 11 is a cross-sectional view taken along the arrow GG in FIG. 4.

[0019] As shown in these figures, the blade holding member 21 is formed in the shape of a bottomed box, with the exposed surface 21A as the bottom surface, and has an internal space 21s that opens to the rear, formed by a front wall portion 21a (see particularly Figures 7 and 10) that corresponds to the bottom, and peripheral walls (right wall 21b, left wall 21c, upper wall 21d and lower wall 21e) (see particularly Figure 4).

[0020] The front wall 21a of the blade holding member 21 is formed with blade holding portions 23 (see Figs. 4, 9, and 11) that hold the blades 12, and a recess 24 (see Figs. 4, 8, and 10) that houses the thermostat 13. More specifically, as shown in Fig. 4, the blade holding member 21 is formed in a generally rectangular shape that is elongated in the vertical direction when viewed from the front, with the recess 24 located from the middle to the upper part of the front wall 21a in the vertical direction, and the blade holding portion 23 located in the lower part of the front wall 21a in the vertical direction.

[0021] 3, recess 24 is formed by recessing a portion of the rear surface of front wall 21a forward relative to the surrounding area so that thermostat 13 can be fitted in from the side of temperature-sensing portion 13a. Thermostat 13 fitted in recess 24 is arranged in a state where it is substantially entirely housed in internal space 21s.

[0022] 1 and 9, the blade holders 23 are formed at positions spaced a predetermined distance apart in the width direction (left-right direction) on the exposed surface 21A in a front view. As shown in Figures 4, 9 and 11, each pair of blade holders 23 has a holder hole 23a penetrating the front wall 21a and a holder space 23b that holds the base 121 of the blade 12 (see Figures 6(a) and 6(b)) inserted into the holder hole 23a.

[0023] When the blade 12 is inserted into the blade holder 23, the tips of the pair of blades 12a, 12b protrude from the exposed surface 21A as shown in Figures 1, 3, and 6(a)(b), and the crimped portion (barrel portion) 121a provided on the base 121 protrudes toward the internal space 21s as shown in Figures 5, 6(a)(b).

[0024] As shown in FIG. 1, a pair of blades 12 are arranged at a predetermined interval in the width direction below the exposed surface 21A, and protrude in a direction perpendicular to the exposed surface 21A so that their tips are parallel to each other.

[0025] Specifically, each of the pair of blades 12a, 12b is formed in a plate shape having a blade surface 123 (see FIG. 1), and is arranged such that the plate thickness direction (the direction in which the pair of blades 12a, 12b are arranged side by side) coincides with the width direction, so that the blade surfaces 123 of the pair of blades 12a, 12b face each other.

[0026] 1 and 9, two grooves 29 extending parallel to each other in the vertical direction are formed in the inter-blade portion 22a of the exposed surface 21A, mainly for increasing the creeping distance between the blades 12. The depth of the grooves 29 is set appropriately, but when the thickness t (see FIG. 3) of the front wall portion 21a corresponding to the bottom of the recess 24 is 2 mm, the depth of the grooves 29 is preferably set to 1 mm.

[0027] 5, in the internal space 21s, the thermostat 13 is disposed adjacent to and above the pair of blades 12a, 12b in a front view. The pair of blades 12a, 12b are oriented such that the gap 12s between the pair of blades 12a, 12b opens toward the thermostat 13 in a front view.

[0028] As shown in Figures 5 and 6(a), the thermostat 13 includes a thermostat main body 131 and a pair of terminal pieces 132 (132a, 132b) that serve as input or output terminals for current to the thermostat main body 131. As shown in Figure 3, the thermostat main body 131 is formed in a cylindrical shape with a temperature sensing part 13a at the front in the axial direction (front-rear direction) and a return switch 13b at the rear.

[0029] Thermostat 13 is a well-known bimetal thermostat that ensures safety by automatically opening the circuit if the temperature detected by temperature-sensing part 13a is abnormal. After the temperature of temperature-sensing part 13a drops, pressing return switch 13b can reset it to detect abnormal temperatures.

[0030] The pair of terminal pieces 132a, 132b protrude from the outer circumferential surface of the thermo main body 131 in opposite directions relative to the thermo main body 131 (at an angle of 180 degrees when viewed from the front) (see FIG. 5). However, as shown in Figures 4 and 5, the pair of terminal pieces 132a, 132b of the thermostat 13 both protrude into a region 12As in the circumferential direction of the thermo main body 131, excluding the gap 12s between the pair of blades 12a, 12b.

[0031] 5, in this embodiment, the pair of terminal pieces 132a, 132b are disposed on both widthwise sides 26r, 26l (i.e., the right region 26r and the left region 26l) of the thermostat body 131. Specifically, of the pair of terminal pieces 132a, 132b, one terminal piece 132a is disposed in the right region 26r of the thermostat body 131, and the other terminal piece 132b is disposed in the left region 26l of the thermostat body 131. That is, one terminal piece 132a is disposed on the same side of the widthwise center of the thermostat 13 as one blade 12a. The other terminal piece 132b is disposed on the same side of the widthwise center of the thermostat 13 as the other blade 12b.

[0032] 4, 5, 6(b), and 7 to 10, a wire introduction opening 25 is formed in the lower wall 21e of the blade holding member 21, recessed forward from the rear end in the central part in the width direction. As a result, the tip end portion 4T (see FIG. 5) of the cord 4 is introduced into the internal space 21s from below the blade holding member 21 through the wire introduction opening 25.

[0033] As shown in Figures 1, 2, and 5, the cord 4 includes a pair of electric wires 14a, 14b, each of which is formed by covering a conductor (core wire) 143 made up of a plurality of conductive wires with an insulating coating 144 (see Figure 2).

[0034] 5 and 6(a) and 6(b), the pair of electric wires 14a, 14b introduced into the internal space 21s are routed at their tip ends in an electric wire routing region 210s in the internal space 21s. The electric wire routing region 210s is a region in the internal space 21s behind the pair of terminal pieces 132a, 132b and the bases 121 of the pair of blades 12a, 12b (see FIGS. 6(a) and 6(b)).

[0035] 4 and 5, the upper part of the electric wire routing region 210s is located on the outer periphery of the thermostat 13 in a front view, i.e., includes a right side region 26r, an upper side region 26u (the side opposite the thermostat 13 from the side having the pair of blades 12a, 12b in a front view), and a left side region 26l in a front view. The lower part of the electric wire routing region 210s is located below the thermostat 13 and above the electric wire inlet 25 in a front view.

[0036] In such an electric wire routing region 210s, of the pair of electric wires 14a, 14b, one electric wire 14a, which is a non-thermoelectric wire, is directly connected to one blade 12a without going through the thermostat 13, as shown in Figures 5 and 6(b), and the other electric wire 14b, which is a thermoelectric wire, is connected to the other blade 12b through the thermostat 13, as shown in Figures 5 and 6(a).

[0037] Specifically, as shown in FIG. 5, the pair of electric wires 14a, 14b are introduced into the electric wire routing region 210s from the outside of the blade holding member 21 through the electric wire introduction port 25 so as to be bifurcated in the width direction at the bottom of the electric wire routing region 210s.

[0038] In addition, one electric wire 14a and the other electric wire 14b (a thermo input electric wire 141b and a thermo output electric wire 142b described later) introduced into the electric wire routing area 210s have their tip ends stripped of their insulating coatings 144 to expose the conductive wires (conductors) 143.

[0039] 5 and 6(b), the tip of one electric wire 14a is connected to the base 121 of one blade 12a at the lower part of the electric wire routing region 210s, thereby forming one blade connecting portion 42a at the connection point.

[0040] On the other hand, as shown in Figures 5 and 6(a), the other wire 14b includes a thermo-input wire 141b and a thermo-output wire 142b. Of these, the thermo-input wire 141b is connected to one terminal piece 132a of the thermostat 13, as shown in Figure 5. As a result, one terminal piece connection portion 41a is formed at the connection point.

[0041] In this case, as shown in FIG. 5, the other electric wire 14b is routed from the lower part to the upper part of the electric wire routing region 210s to the left side region 26l, and routed from the left side region 26l to the right side region 26r via the upper region 26u, and connected to one of the terminal pieces 132a provided in the right side region 26r.

[0042] Furthermore, the thermo output wire 142b provided on the other wire 14b is provided between the other terminal piece 132b of the thermostat 13 and the other blade 12b, i.e., on the left side of the thermostat 13. As shown in FIGS. 5 and 6(a), one end of the thermo output wire 142b is connected to the other terminal piece 132b. This forms the other terminal piece connection part 41b at this connection point. Furthermore, the other end of the thermo output wire 142b is connected to the other blade 12b. This forms the other blade connection part 42b at this connection point.

[0043] In this embodiment, the first blade connection portion 42a and the second blade connection portion 42b are both connections in which the conductor 143 at the tip of the electric wire 14 is crimped (crimped) to the crimping portion 121a of the base 121 of the blade 12. On the other hand, the first terminal piece connection portion 41a and the second terminal piece connection portion 41b are both connections in which the conductor 143 at the tip of the electric wire 14 is welded to the terminal piece 132.

[0044] 5, 6(a), 9, and 10, a first partition 31 is provided in the gap 12s (see FIG. 5) between the pair of blades 12a, 12b to separate the pair of blades 12a, 12b. The first partition 31 extends linearly in the vertical direction in front view so as to divide the lower part of the internal space 21s in the width direction into the side of one blade 12a and the side of the other blade 12b (see FIG. 5).

[0045] 5, 8, and 11, a second partition wall 32 is provided between one terminal piece 132a and one blade 12a to separate the one terminal piece 132a from the one blade 12a. Furthermore, as shown in FIGS. 5, 6(a), and 8, a third partition wall 33 is provided between the other terminal piece 132b and the other blade 12b to separate the other terminal piece 132b from the other blade 12b.

[0046] 5, the second partition wall portion 32 is disposed so that its upper end 32u (the end portion facing one terminal piece 132a in the circumferential direction of the thermostat 13) abuts against one terminal piece 132a from below. On the other hand, the third partition wall portion 33 is disposed so that its upper end 33u (the end portion facing the other terminal piece 132b in the circumferential direction of the thermostat 13) abuts against the other terminal piece 132b from below. As a result, the thermostat 13 is restricted in the circumferential direction by the second partition wall portion 32 and the third partition wall portion 33.

[0047] As shown in FIGS. 3 and 5, a guide portion 34 for guiding the thermo input wire 141b provided on the other wire 14b from the side (below) of the thermostat 13 is provided in the upper region 26u in front view.

[0048] As shown in FIG. 5, the guide portion 34 is interposed between the thermo input electric wire 141b and the thermo main body portion 131 so as to be able to guide the thermo input electric wire 141b from below as it is routed from the left region 26l to the right region 26r in the upper region 26u.

[0049] Furthermore, the guide portion 34 extends in an arc shape along the outer periphery of the thermostat main body 131 in a front view, and continues to extend circumferentially around the thermostat main body 131 until both end portions 34r, 34l abut against the corresponding terminal pieces 132a, 132b. Specifically, the guide portion 34 is disposed so that the right end 34r abuts against one terminal piece 132a from above, and the left end 34l abuts against the other terminal piece 132b from above. This restricts the thermostat 13 in the circumferential direction by the guide portion 34.

[0050] The first partition 31, the second partition 32, the third partition 33, and the guide 34 are all arranged in a layout concentric with the thermo main body 131 so as to surround the thermo main body 131. Furthermore, each of these elements 31, 32, 33, and 34 is provided in an upright rib shape from the rear surface of the front wall 21a, which forms the bottomed box-like concave bottom, to a position rearward of the electric wire routing region 210s, i.e., to the rear end of the blade holding member 21.

[0051] The above-mentioned elements 31, 32, 33, 34 are all arranged so that the surfaces (31a, 32a, 33a, 34a) facing the thermostat main body 131 abut against the thermostat main body 131. Specifically, the first partition wall 31 has an upper end 31a abutting against the outer circumferential surface of the thermostat main body 131 of the thermostat 13, the second partition wall 32 has a left surface 32a abutting against the outer circumferential surface of the thermostat main body 131 of the thermostat 13, the third partition wall 33 has a right surface 33a abutting against the outer circumferential surface of the thermostat main body 131 of the thermostat 13, and the guide portion 34 has a lower surface 34a abutting against the outer circumferential surface of the thermostat main body 131 of the thermostat 13. As a result, each of the elements 31 , 32 , 33 , 34 enhances the holding function of the thermostat 13 held in the recess 24 .

[0052] 5, 7, 8, and 11, reference numeral 35 denotes a recess formed in a thick portion of the blade holding member 21 where sink marks are likely to occur, in order to make the thickness of each portion as uniform as possible as a measure to prevent shrinkage (sink marks) that occurs when the resin cools and hardens after injection molding. The recess 35 is formed in a concave shape extending forward from the rear surface of the front wall 21a.

[0053] 3, 4, 6(a) and 6(b), 7, 9, and 10, reference numeral 36 denotes a through-hole formed in the front wall portion 21a. When the plug body 28 is injection-molded with resin to cover the blade holding member 21, the through-hole 36 allows resins flowing into the through-hole 36 from the front and rear sides to fuse with each other (see FIG. 3). This improves the integrity of the front side (e.g., the resin forming the outer circumferential portion 15a of the front wall portion 21a) and the rear side (the resin filled in the internal space 21s of the blade holding member 21) of the front wall 21a.

[0054] Next, an example of a method for manufacturing the attachment plug 11 will be described. The lead wire 143 (conductor) exposed at the tip of the wire 14a from the insulating coating 144 is crimped by the crimping portion 121a of the blade 12a using a crimping tool (not shown) or the like, thereby connecting the wire 14a to the blade 12a (see FIGS. 5 and 6(b)). In the same manner, the thermo output wire 142b is connected to the blade 12b (see FIGS. 5 and 6(a)).

[0055] Furthermore, a lead wire 143 (conductor) exposed from the insulating coating 144 at the tip of the thermo input wire 141b of the other wire 14b is connected to one terminal piece 132a of the thermostat 13 by spot welding (see FIG. 5). In the same manner, the thermo output wire 142b is connected to the other terminal piece 132b of the thermostat 13 (see FIGS. 5 and 6(a)).

[0056] Next, the pair of electric wires 14a, 14b, together with the thermostat 13 and the blade 12, are mounted on the blade holding member 21, which has been previously formed by injection molding or the like, to change from the state shown in Fig. 4 to the state shown in Fig. 5. At this time, the blade 12 is attached to the blade holding portion 23, and the thermostat 13 is attached to the recess 24, both from the rear side of the blade holding member 21. The electric wires 14 are routed in the electric wire routing region 210s to achieve the layout described above (see Fig. 5).

[0057] Next, the plug body 28 is injection molded using a thermoplastic resin, so that the outer surface of the blade holding member 21, which serves as a core, except for the exposed surface 21A, is covered with the thermoplastic resin that forms the plug body 28.

[0058] Furthermore, the thermostat 13 except for the return switch 13b, the base 121 of the blade 12, and the tip end portions (4T) of the pair of electric wires 14a, 14b are embedded in a thermoplastic resin.

[0059] Furthermore, in this embodiment, during injection molding, molten resin is injected into the mold for the plug body 28 from the gate position GP (see FIG. 2) and flows into the internal space 21s from the wire inlet 25 as viewed from the front toward the thermostat 13 (see the outline arrow Di in FIG. 5). At this time, it is necessary to ensure that the injection pressure is low enough to prevent the resin from flowing into the thermostat 13 through the gaps at the bases of the pair of terminal pieces 132a, 132b (the gaps between the case of the thermo main body 131 and the terminal pieces 132a, 132b) (not shown), while still ensuring that the injection pressure is low enough to prevent welds (resin merging marks) from remaining on the surface of the plug body 28 after molding or defects such as insufficient filling, particularly in thin-walled portions.

[0060] Finally, the exposed surface 21A is intentionally overheated by, for example, contacting a heater plate (not shown) heated to a predetermined overheating temperature with the exposed surface 21A, and a quality inspection is performed to determine whether the thermostat 13 operates properly. In this manner, the attachment plug 11 can be manufactured.

[0061] As shown in FIGS. 1 to 3, the attachment plug 11 of the present embodiment described above comprises a thermostat 13 that detects an overheating state and cuts off the current, a plug body 15 incorporating the thermostat 13, and a pair of blades 12 (12a, 12b) that protrude outward from the plug body 15 and are arranged in parallel and spaced apart from each other in a front view (see FIGS. 1 and 2). The thermostat 13 has a pair of electric wires 14 (14a, 14b) connected to the thermostat main body 131 (see Figures 2, 3, and 5), and the thermostat 13 has a thermostat main body 131 and a pair of terminal pieces 132 (132a, 132b) to which the electric wires 14 are connected and which protrude from the thermostat main body 131 in a front view (see Figures 1 to 3 and 5), and each of the pair of terminal pieces 132a, 132b is disposed in a region 12As excluding the gap 12s between the pair of blades 12a, 12b (see Figures 4 and 5).

[0062] Compared with a configuration in which the terminal piece (132a or 132b) is disposed in the gap 12s between the pair of blades 12a, 12b, this configuration makes it easier to separate the connection between the blade 12 and the wire 14 and the connection between the terminal piece 132 and the wire 14. This prevents the two connection parts from accidentally coming into contact with each other, resulting in a short circuit or malfunction of the thermostat 13.

[0063] Specifically, since one blade 12a and one terminal piece 132a are of opposite polarity, if the wires constituting the conductor 143 at the tip of the electric wire 14 connected thereto become loose, one blade connection portion 42a (see FIG. 5) and one terminal piece connection portion 41a (see the same figure) may come into unintended contact with each other, which may result in a malfunction such as a short circuit. Similarly, one blade 12a and the other terminal piece 132b are of opposite polarity, so if they come into contact with each other, there is a risk of a malfunction such as a short circuit.

[0064] Furthermore, although the other blade 12b and one terminal piece 132a are of the same polarity, as described above, if the other blade connection portion 42b and one terminal piece connection portion 41a come into unintentional contact with each other due to reasons such as fraying of the wires constituting the conductor 143, there is a risk that the thermostat 13 will not function properly.

[0065] In contrast, as described above, by configuring the pair of terminal pieces 132a, 132b of the thermostat 13 to be disposed in a region 12As excluding the gap 12s between the pair of blades 12a, 12b in the circumferential direction of the thermo main body 131 in a front view, it becomes easier to separate the one terminal piece connection portion 41a and the other terminal piece connection portion 41b from the one blade connection portion 42a and the other blade connection portion 42b (in other words, it becomes easier to ensure a physical distance), thereby preventing unintended contact with each other. This prevents problems such as short circuits and improper operation of the thermostat 13.

[0066] As shown in Figures 2 to 6(a) and 7 to 10, in an embodiment of the present invention, a first partition wall portion 31 is provided in the gap 12s between the pair of blades 12a, 12b to separate the pair of blades 12a, 12b from each other.

[0067] According to the above configuration, the pair of blades 12a, 12b, which are opposite poles to each other, are isolated from each other by the first partition portion 31 provided between the pair of blades 12a, 12b, thereby preventing problems such as short circuits caused by unintended contact between one blade connection portion 42a and the other blade connection portion 42b.

[0068] Furthermore, as described above, by arranging each of the pair of terminal pieces 132a, 132b of the thermostat 13 in the portion 12As other than the gap 12s between the pair of blades 12a, 12b, and not arranging them in the gap 12s (see Figures 4 and 5), the gap 12s can be effectively utilized as space for providing the first partition wall portion 31.

[0069] As shown in Figures 2, 4 and 5, in an embodiment of the present invention, of the pair of blades 12a, 12b, the blade 12 to which the tip of one electric wire 14a (the electric wire not passing through the thermostat 13) is connected is set as one blade 12a, and of the pair of terminal pieces 132a, 132b, the terminal piece 132 located in the right region 26r in front view (the terminal piece located adjacent to the one blade 12a on the side opposite to the first partition wall 31) is set as one terminal piece 132a (one-side terminal piece), and a second partition wall 32 is provided between the one terminal piece 132a and the one blade 12a to separate the one terminal piece 132a and the one blade 12a (see Figures 4 and 5).

[0070] According to the above configuration, one terminal piece 132a and one blade 12a, which are of opposite polarity, are isolated from each other by the second partition portion 32 provided between them, thereby preventing defects such as a short circuit caused by one terminal piece connection portion 41a and one blade connection portion 42a coming into unintentional contact with each other (see Figure 5).

[0071] As shown in Figures 4 and 5, in an embodiment of the present invention, the region above the thermostat 13 in a front view (opposite the side of the pair of blades 12a, 12b) is set as an upper region 26u (a region where no blades are arranged), and as shown in Figure 5, of the pair of electric wires 14a, 14b, the thermo input electric wire 141b provided on the other electric wire 14b that interposes the thermostat 13 is routed from the left region 26l (opposite the side of one terminal piece 132a) of the thermostat 13 in a front view to the one terminal piece 132a via the upper region 26u, and a guide portion 34 that guides the thermo input electric wire 141b from the side of the thermostat 13 is provided in the upper region 26u.

[0072] According to the above configuration, when a tensile load is applied to the tip portion 4T of the cord 4 (the pair of electric wires 14) toward the outside of the plug body 15, the portion of the thermo-input electric wire 141b that is guided by the guide portion 34 comes into closer contact with the guide portion 34. In other words, the contact resistance between the guide portion 34 and the thermo-input electric wire 141b increases, and the tensile load can be effectively received by the guide portion 34.

[0073] Therefore, since a tensile load is not directly applied to the one terminal piece connecting portion 41a, a strong connection state between the one terminal piece 132a and the thermo input wire 141b can be maintained.

[0074] As shown in Figure 5, in an embodiment of the present invention, the guide portion 34 is configured to extend continuously along the circumferential direction of the thermo main body 131 when viewed from the front until both end portions 34r, 34l abut against the corresponding terminal pieces 132a, 132b, respectively.

[0075] According to the above configuration, the two end portions 34r, 34l in the extending direction of the guide portion 34 abut against the corresponding terminal pieces 132a, 132b, thereby restricting the displacement of the thermostat 13 in the circumferential direction.

[0076] Furthermore, the guide portion 34 can guide (contact) the other electric wire 14b (thermo input electric wire 141b) over the entire area between the pair of terminal pieces 132a, 132b in the upper region 26u, thereby ensuring a sufficient contact area with the other electric wire 14b.

[0077] Therefore, even if a tensile load is applied to the tip portion 4T of the cord 4 (the pair of electric wires 14) toward the outside of the plug body 15, the load applied to one terminal piece connecting portion 41a can be further alleviated.

[0078] As shown in the same figure, in an embodiment of this invention, the first partition portion 31, the second partition portion 32, the third partition portion 33 and the guide portion 34 are arranged so that the opposing surfaces 31a, 32a, 33a and 34a with the thermo main body portion 131 abut against the outer peripheral surface of the thermo main body portion 131.

[0079] According to the above-described configuration, the thermostat main body 131 can be held so that the thermostat 13 does not shift position in the plug main body 15 when viewed from the front.

[0080] As shown in Figures 1, 2, 4 and 5, in an embodiment of the present invention, a pair of terminal pieces 132a, 132b are arranged on each side (right and left sides) of the thermo main body 131 in the width direction.

[0081] According to the above configuration, each of the pair of terminal pieces 132a, 132b has a polarity opposite to that of one of the pair of blades 12a, 12b, particularly to one of the blades 12a, but they can be arranged approximately evenly and as far apart as possible from that one of the blades 12a.

[0082] This prevents problems such as short circuits caused by one terminal piece connection portion 41a (see Figure 5) and the other terminal piece connection portion 41b (see Figure 5) unintentionally coming into contact with one blade connection portion 42a (see Figure 5) by maintaining a physical distance.

[0083] Furthermore, with the above configuration, the pair of terminal pieces 132a, 132b can be disposed in opposite positions across the center of the thermo main body 131 when viewed from the front (see FIG. 5), and therefore the pair of terminal pieces 132a, 132b can also be disposed as far apart as possible from each other in the circumferential direction of the thermostat 13. This ensures a physical distance between one terminal piece connection portion 41a (see FIG. 5) and the other terminal piece connection portion 41b (see FIG. 5) so that they do not come into contact with each other unintentionally.

[0084] Furthermore, malfunction of the thermostat 13 can be prevented during molding of the plug body 28. More specifically, when the plug body 28 is injection molded, as described above, molten resin is flowed into the internal space 21s from the wire inlet 25 toward the thermostat 13 (see the white arrow Di in FIG. 5).

[0085] Therefore, as described above, by arranging the pair of terminal pieces 132a, 132b on both sides of the width of the thermostat 13, each of the pair of terminal pieces 132a, 132b can be equally spaced away from the position of the wire inlet 25 (in other words, the gate position GP (see Figure 2)). This allows the pair of terminal pieces 132a, 132b to be arranged so that the injection pressure during molding acts on the respective bases in a state where it is evenly relaxed.

[0086] Therefore, during molding, it is possible to prevent resin from flowing into the interior of the thermostat 13 through the gap at the base of the terminal pieces 132a, 132b (the gap between the case of the thermo main body 131 and the terminal pieces 132a, 132b) (not shown), thereby preventing the thermostat 13 from malfunctioning.

[0087] Furthermore, as described above, since the occurrence of defects in the thermostat 13 can be suppressed even when the injection pressure is increased, the injection pressure can be increased to prevent defects such as residual welds (resin merging marks) and insufficient filling of thin-walled portions. This also improves the appearance design of the plug body 15.

[0088] As shown in Figures 5 and 6(a), in an embodiment of the present invention, the other blade 12b to which the tip of the other electric wire 14b (thermo output electric wire 142b) is connected and the other terminal piece 132b are arranged on the same left side of the center of the thermostat 13 in the width direction (the direction in which the pair of blades are arranged in parallel).

[0089] The other blade 12b and the other terminal piece 132b are at the same potential. Therefore, as described above, by arranging the other blade 12b and the other terminal piece 132b on the same side of the center of the thermostat 13, there is no risk of a short circuit or other problem even if they come into contact with each other, and an overall compact layout can be achieved.

[0090] The present invention is not limited to the configurations of the above-described embodiments, but can be formed in various other embodiments.

[0091] For example, in the present invention, as long as each of the pair of terminal pieces 132a, 132b is arranged in a region 12As excluding the gap 12s between the pair of blades 12a, 12b, it is not limited to the configuration in which they are arranged on both sides 26r, 26l (i.e., the right region 26r and the left region 26l) of the width direction of the thermo main body 131 as in the above-described embodiment (see Figure 5), but the terminal pieces may be arranged in any region.

[0092] Furthermore, the layout of the thermostat 13, the pair of blades 12a, 12b, and the pair of electric wires 14a, 14b in the internal space 21s employed in the above-described embodiment is one example, and the present invention is not limited to the above-described layout. For example, the elements 13, 12a, 12b, and the electric wires 14a, 14b may be arranged in the internal space 21s so as to be symmetrical to the layout of the above-described embodiment. [Explanation of symbols]

[0093] 11...Attachment plug 13...Thermostat 15...Plug body 12(12a,12b)…Bung blade 12a...One of the blades (one side blade) 12b...the other blade (the other side blade) 12s: Gap between a pair of blades (between a pair of blades) 12As...Area excluding the gap between a pair of blades (area excluding the area between a pair of blades) 14(14a,14b)…Electric wire 14a...One of the wires (wire without thermostat) 14b...The other wire (thermo-interposed wire) 21s...Internal space (inside the plug body) 26r: Right side region (opposite the first partition portion side with respect to the one blade in front view) 26u…Upper area (area where plug blade is not placed) 26l...Left side region (opposite the side of the thermostat from the side of the one terminal piece when viewed from the front) 31...First partition part, partition part 31a...the surface of the first partition wall facing the thermo body 32...Second bulkhead part 32a...the surface of the second partition wall facing the thermo body 34...Guide part 34a... Surface of the guide portion facing the thermo body 34r, 34l...Both ends of the guide section 131...Thermo main body 132 (132a, 132b)...Pair of terminal pieces 132a...One terminal piece (one side terminal piece) 132b...other terminal piece (other side terminal piece)

Claims

[Claim 1] A thermostat that detects overheating and cuts off the current; a plug body incorporating the thermostat; a pair of blades protruding outward from the plug body and arranged in parallel on the left and right sides and spaced apart from each other in a front view; a pair of electric wires introduced into the plug body from a direction perpendicular to the protruding direction of the blades on the outside of the plug body and connected to the corresponding blades, The thermostat includes a thermostat main body and a pair of terminal pieces to which the electric wire is connected and which protrude in opposite directions from the thermostat main body in a front view. The pair of terminal pieces are arranged parallel to the direction in which the pair of blades are arranged side by side, and are evenly spaced apart on the left and right. Insertion plug.

Images